[parisc-linux] stale references to io_request_lock

[Grant Grundler]

Willy,
your favorite scsi driver still has references to io_request_lock in
it's comments:
...
 *  The whole SCSI sub-system under Linux is basically single-threaded.
 *  Everything, including low-level driver interrupt routine, happens
 *  with the `io_request_lock' held.
...

I was looking at what else might not have been forward ported
and stumbled across this reference. Care to delete it?

thanks,
grant