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 <[e-mail]>
Signed-off-by: Kyungmin Park <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/exynos/exynos_drm_g2d.c

···
 					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);