linux-raspberrypi-dev: Switch to rpi-4.12.y
linux-raspberrypi-dev: Switch to rpi-4.12.y

Linux v4.12 is now released.

Signed-off-by: Paul Barker <ea07171fd37de70b22964565a4c2bfd2bb2b3061@toganlabs.com>

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