changes to cam_xpt to support sequential scanning (!parallel)

[Matt Jacob]

>Sounds like a good idea to me.  It'll allow us to also do the same thing
>for any other devices that come along that can't handle the parallel probe.
>
>I took a brief look through it, but I haven't reviewed it in detail.  It
>looks like there are a few whitespace type changes.

Yeah, sorry. I'll back those out.

>> The code also does some cleanups under failure conditions.
>> 
>> After a bit more testing I'd like to put this in if there are no
>> objections so I can get the mpt U320 stuff off my back for a while.
>
>I would say go for it if things seem to work well.  (I'm assuming you've
>also tested it with an Adaptec, Qlogic or some other controller that works
>with the parallel scan?)

Yes, I will have completed testing with:

  Adaptec 2940
  Symbios 53c95
  Qlogic 1040

*and* with some narrow/async targets other than SES before I do a checkin.

Thanks!