drm/v3d: add missing mutex_destroy

v3d_perfmon_open_file() instantiates a mutex for a particular file
instance, but it never destroys it by calling mutex_destroy() in
v3d_perfmon_close_file().

Similarly, v3d_perfmon_create_ioctl() instantiates a mutex for a
particular perfmon, but it never destroys it by calling mutex_destroy()
in v3d_perfmon_destroy_ioctl().

So, add the missing mutex_destroy on both cases.
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221108175425.39819-3-mcanal@igalia.com

drivers/gpu/drm/v3d/v3d_perfmon.c

@@ -17,8 +17,10 @@ void v3d_perfmon_get(struct v3d_perfmon *perfmon)
 
 void v3d_perfmon_put(struct v3d_perfmon *perfmon)
 {
-	if (perfmon && refcount_dec_and_test(&perfmon->refcnt))
+	if (perfmon && refcount_dec_and_test(&perfmon->refcnt)) {
+		mutex_destroy(&perfmon->lock);
 		kfree(perfmon);
+	}
 }
 
 void v3d_perfmon_start(struct v3d_dev *v3d, struct v3d_perfmon *perfmon)
@@ -113,6 +115,7 @@ void v3d_perfmon_close_file(struct v3d_file_priv *v3d_priv)
 	idr_for_each(&v3d_priv->perfmon.idr, v3d_perfmon_idr_del, NULL);
 	idr_destroy(&v3d_priv->perfmon.idr);
 	mutex_unlock(&v3d_priv->perfmon.lock);
+	mutex_destroy(&v3d_priv->perfmon.lock);
 }
 
 int v3d_perfmon_create_ioctl(struct drm_device *dev, void *data,
@@ -154,6 +157,7 @@ int v3d_perfmon_create_ioctl(struct drm_device *dev, void *data,
 	mutex_unlock(&v3d_priv->perfmon.lock);
 
 	if (ret < 0) {
+		mutex_destroy(&perfmon->lock);
 		kfree(perfmon);
 		return ret;
 	}