generic: Base upon ArchAPI
generic: Base upon ArchAPI

As generic is often picked as our 'odd-one-out' we also use it as an
example of an Arch that does not build upon BaseArch.

Signed-off-by: D. Shah <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@ds0.me>

SymbiFlow/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,YosysHQ/nextpnr,YosysHQ/nextpnr