docs: trace: fix the location of kprobes.rst

This patch was moved out of staging.

Fixes: 2165b82f ("docs: Move kprobes.rst from staging/ to trace/")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/a6d4c62e19ab1510789418a3a5ad42980cd7ae3a.1599660067.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/trace/kprobetrace.rst

@@ -40,7 +40,7 @@ Synopsis of kprobe_events
  MEMADDR	: Address where the probe is inserted.
  MAXACTIVE	: Maximum number of instances of the specified function that
 		  can be probed simultaneously, or 0 for the default value
-		  as defined in Documentation/staging/kprobes.rst section 1.3.1.
+		  as defined in Documentation/trace/kprobes.rst section 1.3.1.
 
  FETCHARGS	: Arguments. Each probe can have up to 128 args.
   %REG		: Fetch register REG

samples/kprobes/kprobe_example.c

@@ -5,7 +5,7 @@
  * stack trace and selected registers when _do_fork() is called.
  *
  * For more information on theory of operation of kprobes, see
- * Documentation/staging/kprobes.rst
+ * Documentation/trace/kprobes.rst
  *
  * You will see the trace data in /var/log/messages and on the console
  * whenever _do_fork() is invoked to create a new process.

samples/kprobes/kretprobe_example.c

@@ -11,7 +11,7 @@
  * If no func_name is specified, _do_fork is instrumented
  *
  * For more information on theory of operation of kretprobes, see
- * Documentation/staging/kprobes.rst
+ * Documentation/trace/kprobes.rst
  *
  * Build and insert the kernel module as done in the kprobe example.
  * You will see the trace data in /var/log/messages and on the console