docs: trace: fix the location of kprobes.rst

This patch was moved out of staging.

Fixes: 2165b82fde82 ("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.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
index 78a2da6..69fd1235 100644
--- a/samples/kprobes/kretprobe_example.c
+++ b/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