cm: add sepolicy entry for lockscreen wallpaper

Change-Id: Ie779392ab8118d192873a01ec5c7de3e5938ed17
Signed-off-by: Roman Birg <roman@cyngn.com>
Sepolicy: Add theme service as system service

Change-Id: Idfb690be5d35c03610165b914c0a3f2260e68956