drm/hisilicon: Use lockless gem BO free callback

No dev->struct_mutex anywhere to be seen.

Cc: Xinliang Liu <xinliang.liu@linaro.org>
Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-27-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c

@@ -173,7 +173,7 @@ static struct drm_driver kirin_drm_driver = {
 	.fops			= &kirin_drm_fops,
 	.set_busid		= drm_platform_set_busid,
 
-	.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,
 	.dumb_create		= kirin_gem_cma_dumb_create,
 	.dumb_map_offset	= drm_gem_cma_dumb_map_offset,