layer.conf: Drop gatesgarth and add honister to LAYERSERIES_COMPAT
layer.conf: Drop gatesgarth and add honister to LAYERSERIES_COMPAT

master can only be validated with latest WIP oe-core releases so drop
gatesgrath which is now a dedicated release, soon hardknott will be out
too but for master needs its fine, while hear add honister ( fall 2021 )
release too

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi