[9fans] 9fs and 1542

[jmk@plan9.bell-labs.com jmk@plan9.bell-labs.com]

I'll echo the concerns about termination and also to double-check
the kernel is correctly determining the cpu speed for delay loops.

That said, I've looked at the Plan9 fs scsiprobe routine and I'd just
take out the loop, turning

	status = 0;
	for(t = 0; t < 3; t++) {
		status = testur(ctlr, d);
		if(status == 0x6000)
			break;
	}

into

	status = testur(ctlr, d);

I don't know why the loop is there, it's probably a hangover
from some buggy hardware in the distant past - some of this code
dates from a Unibus controller on a Vax-11/750 - the current fs code
doesn't do this. The loop shouldn't cause any problems, but it
might be interacting with some marginal hardware problem.

--jim