openpixelcontrol/soma_server.c: Remove support for the old protocol
openpixelcontrol/soma_server.c: Remove support for the old protocol

It's been seven years since we used the "old" protocol on the RS-485
bus.  Clean up the code base a bit by removing support for it.

FlamingLotusGirls/soma,FlamingLotusGirls/soma,FlamingLotusGirls/soma,FlamingLotusGirls/soma,FlamingLotusGirls/soma,FlamingLotusGirls/soma,FlamingLotusGirls/soma