drm/pl111: Use gem_free_object_unlocked

CMA helpers are struct_mutex free, and so is the pl111 itself. And
that's the only valid reason for using gem_free_object.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20170717151045.4188-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/pl111/pl111_drv.c

@@ -161,7 +161,7 @@ static struct drm_driver pl111_drm_driver = {
 	.dumb_create = drm_gem_cma_dumb_create,
 	.dumb_destroy = drm_gem_dumb_destroy,
 	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
-	.gem_free_object = drm_gem_cma_free_object,
+	.gem_free_object_unlocked = drm_gem_cma_free_object,
 	.gem_vm_ops = &drm_gem_cma_vm_ops,
 
 	.enable_vblank = pl111_enable_vblank,