hi,

I've updated the scc driver and eliminated the need to use the PROM
between initial bootstrap and when kernel autoconfiguration finds the
SCC device. Serial booting is slightly faster :) and the message about
``using the PROM...'' is gone.

I've tested this on a 5000/150 and a 5000/50, and also requested the
changes be pulled up for the 1.3.3 release.

as usual, if you  have any problems, send a PR.