drm/qxl: unref cursor bo when finished with it

qxl_cursor_atomic_update allocs a bo for the cursor that
it never frees up at the end of the function.

This commit fixes that.
Signed-off-by: Ray Strode <rstrode@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/qxl/qxl_display.c

@@ -575,7 +575,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 	struct qxl_cursor_cmd *cmd;
 	struct qxl_cursor *cursor;
 	struct drm_gem_object *obj;
-	struct qxl_bo *cursor_bo, *user_bo = NULL;
+	struct qxl_bo *cursor_bo = NULL, *user_bo = NULL;
 	int ret;
 	void *user_ptr;
 	int size = 64*64*4;
@@ -645,6 +645,8 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 	qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
 	qxl_release_fence_buffer_objects(release);
 
+	qxl_bo_unref(&cursor_bo);
+
 	return;
 
 out_backoff: