drm/sti: Use lockless gem BO free callback

With Benjanim's patch to remove the dev->struct_mutex cargo cult the
sti driver is now also entirely legacy locking free. Let's convert it
too.

Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-20-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/sti/sti_drv.c

@@ -304,7 +304,7 @@ static struct drm_driver sti_driver = {
 	.driver_features = DRIVER_HAVE_IRQ | DRIVER_MODESET |
 	    DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
 	.load = sti_load,
-	.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 = drm_gem_cma_dumb_create,
 	.dumb_map_offset = drm_gem_cma_dumb_map_offset,