arm64: dts: renesas: condor: switch from EtherAVB to GEther

The "official" Condor boards have always been wired to mount NFS via
GEther, not EtherAVB -- the boards resoldered for EtherAVB were local
to Cogent Embedded, so we've been having an unpleasant situation where
a "normal" Condor board still can't mount NFS (unless an EtherAVB PHY
extension board is plugged in). Switch from EtherAVB to GEther at last!

Fixes: 8091788f

 ("arm64: dts: renesas: condor: add EtherAVB support")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>