higher level scsi code.
Spls should never be conditionalized, so don't do so here.
Restructure the get_ccb routine so that we can't get into an infinite
loop if the ccbs are exhausted and we are are called with SCSI_NOSLEEP set.
Other driver maintainer's that based their ccb allocation routines on Julian's
code should look at these changes and implement them for their driver.
Submitted by: John Dyson