gpu/drm: clean up white space in drm_legacy_lock_master_cleanup()

We moved this code to a different file and accidentally deleted a
newline.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200108054312.yzlj5wmbdktejgob@kili.mountain

drivers/gpu/drm/drm_lock.c

@@ -360,7 +360,8 @@ void drm_legacy_lock_master_cleanup(struct drm_device *dev, struct drm_master *m
 	/*
 	 * Since the master is disappearing, so is the
 	 * possibility to lock.
-	 */	mutex_lock(&dev->struct_mutex);
+	 */
+	mutex_lock(&dev->struct_mutex);
 	if (master->lock.hw_lock) {
 		if (dev->sigdata.lock == master->lock.hw_lock)
 			dev->sigdata.lock = NULL;