linux-raspberrypi: Change default version to 4.14.y
linux-raspberrypi: Change default version to 4.14.y

This matches the change made in the upstream firmware repository earlier in
February.

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

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