drm/atmel: Use lockless gem BO free callback

No dev->struct_mutex anywhere to be seen.

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-4-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c

@@ -776,7 +776,7 @@ static struct drm_driver atmel_hlcdc_dc_driver = {
 	.get_vblank_counter = drm_vblank_no_hw_counter,
 	.enable_vblank = atmel_hlcdc_dc_enable_vblank,
 	.disable_vblank = atmel_hlcdc_dc_disable_vblank,
-	.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,
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,