drm/exynos: g2d: fix memory leak to userptr

This patch releases a vma object when cleaning up userptr resources.
A new vma object was allocated and copied when getting userptr pages
so the new vma object should be freed properly if the userptr pages
aren't used anymore.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/exynos/exynos_drm_g2d.c

@@ -383,6 +383,8 @@ out:
 					g2d_userptr->npages,
 					g2d_userptr->vma);
 
+	exynos_gem_put_vma(g2d_userptr->vma);
+
 	if (!g2d_userptr->out_of_list)
 		list_del_init(&g2d_userptr->list);