Distinguish between the different variants and configurations of Sunix
{MIO,SER}5xxxx chips instead of treating all of them as PUC_PORT_2S.
Among others, this fixes the hang seen when trying to probe the none-
existent second UART on an actually 1-port chip.

Obtained from: NetBSD (BAR layouts)
MFC after: 3 days
Sponsored by: Bally Wulff Games & Entertainment GmbH