Documentation: fix filesystems/locking.rst malformed table warnings

Fix Sphinx malformed table warnings in filesystems/locking.rst:

lnx-58-rc1/Documentation/filesystems/locking.rst:443: WARNING: Malformed table.
Text in column margin in table line 8.

lnx-58-rc1/Documentation/filesystems/locking.rst:620: WARNING: Malformed table.
Text in column margin in table line 2.

Fixes: ec23eb54 ("docs: fs: convert docs without extension to ReST")
Fixes: c1e8d7c6 ("mmap locking API: convert mmap_sem comments")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Michel Lespinasse <walken@google.com>
Link: https://lore.kernel.org/r/12c2afd1-2dcf-2ea0-02aa-bc2759729c77@infradead.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/locking.rst

@@ -433,15 +433,15 @@ prototypes::
 
 locking rules:
 
-==========		=============	=================	=========
+======================	=============	=================	=========
 ops			inode->i_lock	blocked_lock_lock	may block
-==========		=============	=================	=========
+======================	=============	=================	=========
 lm_notify:		yes		yes			no
 lm_grant:		no		no			no
 lm_break:		yes		no			no
 lm_change		yes		no			no
 lm_breaker_owns_lease:	no		no			no
-==========		=============	=================	=========
+======================	=============	=================	=========
 
 buffer_head
 ===========
@@ -616,9 +616,9 @@ prototypes::
 
 locking rules:
 
-=============	========	===========================
+=============	=========	===========================
 ops		mmap_lock	PageLocked(page)
-=============	========	===========================
+=============	=========	===========================
 open:		yes
 close:		yes
 fault:		yes		can return with page locked
@@ -626,7 +626,7 @@ map_pages:	yes
 page_mkwrite:	yes		can return with page locked
 pfn_mkwrite:	yes
 access:		yes
-=============	========	===========================
+=============	=========	===========================
 
 ->fault() is called when a previously not present pte is about
 to be faulted in. The filesystem must find and return the page associated