locking.rst: add captions to two tables

Those tables have a "caption" at the end, but ReST
actually expects it on a different way.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/kernel-hacking/locking.rst

@@ -29,43 +29,45 @@ In a normal program, you can increment a counter like so:
 
 This is what they would expect to happen:
 
-+------------------------------------+------------------------------------+
-| Instance 1                         | Instance 2                         |
-+====================================+====================================+
-| read very_important_count (5)      |                                    |
-+------------------------------------+------------------------------------+
-| add 1 (6)                          |                                    |
-+------------------------------------+------------------------------------+
-| write very_important_count (6)     |                                    |
-+------------------------------------+------------------------------------+
-|                                    | read very_important_count (6)      |
-+------------------------------------+------------------------------------+
-|                                    | add 1 (7)                          |
-+------------------------------------+------------------------------------+
-|                                    | write very_important_count (7)     |
-+------------------------------------+------------------------------------+
-
-Table: Expected Results
+
+.. table:: Expected Results
+
+  +------------------------------------+------------------------------------+
+  | Instance 1                         | Instance 2                         |
+  +====================================+====================================+
+  | read very_important_count (5)      |                                    |
+  +------------------------------------+------------------------------------+
+  | add 1 (6)                          |                                    |
+  +------------------------------------+------------------------------------+
+  | write very_important_count (6)     |                                    |
+  +------------------------------------+------------------------------------+
+  |                                    | read very_important_count (6)      |
+  +------------------------------------+------------------------------------+
+  |                                    | add 1 (7)                          |
+  +------------------------------------+------------------------------------+
+  |                                    | write very_important_count (7)     |
+  +------------------------------------+------------------------------------+
 
 This is what might happen:
 
-+------------------------------------+------------------------------------+
-| Instance 1                         | Instance 2                         |
-+====================================+====================================+
-| read very_important_count (5)      |                                    |
-+------------------------------------+------------------------------------+
-|                                    | read very_important_count (5)      |
-+------------------------------------+------------------------------------+
-| add 1 (6)                          |                                    |
-+------------------------------------+------------------------------------+
-|                                    | add 1 (6)                          |
-+------------------------------------+------------------------------------+
-| write very_important_count (6)     |                                    |
-+------------------------------------+------------------------------------+
-|                                    | write very_important_count (6)     |
-+------------------------------------+------------------------------------+
-
-Table: Possible Results
+.. table:: Possible Results
+
+  +------------------------------------+------------------------------------+
+  | Instance 1                         | Instance 2                         |
+  +====================================+====================================+
+  | read very_important_count (5)      |                                    |
+  +------------------------------------+------------------------------------+
+  |                                    | read very_important_count (5)      |
+  +------------------------------------+------------------------------------+
+  | add 1 (6)                          |                                    |
+  +------------------------------------+------------------------------------+
+  |                                    | add 1 (6)                          |
+  +------------------------------------+------------------------------------+
+  | write very_important_count (6)     |                                    |
+  +------------------------------------+------------------------------------+
+  |                                    | write very_important_count (6)     |
+  +------------------------------------+------------------------------------+
+
 
 Race Conditions and Critical Regions
 ------------------------------------