linux-raspberrypi_4.8.bb: upgrade to 4.8.12
linux-raspberrypi_4.8.bb: upgrade to 4.8.12

The rpi-4.8.y branch of git://github.com/raspberrypi/linux.git was rebased,
losing any previous commit hashes. This latest update doesn't include the
raspberry pi patches for 4.8.6, but the upstream patches are included starting
with 4.8.11.

Signed-off-by: Trevor Woerner <8835777cd84fba3d7873eabbbe1f2de2d3f25b00@gmail.com>
Signed-off-by: Andrei Gherzan <8dc7c09356db0b1762fb140617d7375c0a5a4131@gherzan.ro>

LocutusOfBorg/meta-raspberrypi,kraj/meta-raspberrypi,leon-anavi/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,leon-anavi/meta-raspberrypi,kraj/meta-raspberrypi,schnitzeltony/meta-raspberrypi,d21d3q/meta-raspberrypi,toolmmy/meta-raspberrypi,kraj/meta-raspberrypi,leon-anavi/meta-raspberrypi,toolmmy/meta-raspberrypi,agherzan/meta-raspberrypi,d21d3q/meta-raspberrypi,agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,schnitzeltony/meta-raspberrypi,d21d3q/meta-raspberrypi,toolmmy/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,d21d3q/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,toolmmy/meta-raspberrypi