userland: Use commit date as PV
userland: Use commit date as PV

This gives us a package version which can be reliably expected to move forwards
not backwards.

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

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