drm/msm: fix deadlock in bo create fail path

We already hold struct_mutex here.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index d8d60c9..3da8264 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -644,7 +644,7 @@
 
 fail:
 	if (obj)
-		drm_gem_object_unreference_unlocked(obj);
+		drm_gem_object_unreference(obj);
 
 	return ERR_PTR(ret);
 }