No dev->struct_mutex anywhere to be seen.

Cc: Jianwei Wang <jianwei.wang.chn@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-7-git-send-email-daniel.vetter@ffwll.ch