reject them for simple commands. Leo W. reports that this does
not work for some systems. It's better than what we have now,
though. From Paul Goyette <paul@pgoyette.bdt.com>.
MSG_REJECT_MESSAGE instead of MSG_ABORT when we get an extended message.
This allows a DEC drive to work when it attempts to negotiate synch.
transfers on us.
I added two new bitfields to ncr_softc. They flag which devices have
been selected, and which ones have failed to go to message out when
selected with ATN. If a target fails to go to message out the first
time it is selected, it goes into the latter bitfield. If it fails
thereafter, we treat it as we did before.