drm/i915/perf: Fix kernel-doc warning

Fix kernel-doc issue from a previous commit.
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Fixes: 2db609c0 ("drm/i915/perf: Replace gt->perf.lock with stream->lock for file ops")
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221107202410.1976895-1-umesh.nerlige.ramappa@intel.com

drivers/gpu/drm/i915/i915_perf_types.h

@@ -146,8 +146,8 @@ struct i915_perf_stream {
 	 */
 	struct intel_engine_cs *engine;
 
-	/*
-	 * Lock associated with operations on stream
+	/**
+	 * @lock: Lock associated with operations on stream
 	 */
 	struct mutex lock;