tracepoints: API doc update to data argument

Describe the @data argument (probe private data).

Link: http://lkml.kernel.org/r/1394587948-27878-1-git-send-email-mathieu.desnoyers@efficios.com

Fixes: 38516ab "tracing: Let tracepoints have data passed to tracepoint callbacks"
CC: Ingo Molnar <mingo@kernel.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/tracepoint.c

@@ -376,6 +376,7 @@ tracepoint_add_probe(const char *name, void *probe, void *data)
  * tracepoint_probe_register -  Connect a probe to a tracepoint
  * @name: tracepoint name
  * @probe: probe handler
+ * @data: probe private data
  *
  * Returns 0 if ok, error value on error.
  * The probe address must at least be aligned on the architecture pointer size.
@@ -424,6 +425,7 @@ tracepoint_remove_probe(const char *name, void *probe, void *data)
  * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
  * @name: tracepoint name
  * @probe: probe function pointer
+ * @data: probe private data
  *
  * We do not need to call a synchronize_sched to make sure the probes have
  * finished running before doing a module unload, because the module unload
@@ -464,6 +466,7 @@ static void tracepoint_add_old_probes(void *old)
  * tracepoint_probe_register_noupdate -  register a probe but not connect
  * @name: tracepoint name
  * @probe: probe handler
+ * @data: probe private data
  *
  * caller must call tracepoint_probe_update_all()
  */
@@ -488,6 +491,7 @@ EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
  * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
  * @name: tracepoint name
  * @probe: probe function pointer
+ * @data: probe private data
  *
  * caller must call tracepoint_probe_update_all()
  */