linux-raspberrypi: add linux-raspberrypi-rt 4.14
linux-raspberrypi: add linux-raspberrypi-rt 4.14

select the rt kernel by adding in local.conf:

PREFERRED_PROVIDER_virtual/kernel = "linux-raspberrypi-rt"

Signed-off-by: Phong Tran <ef5cc4595e4f7ef6b60cbdfeace4845b7e64bdaf@gmail.com>

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