in how interrupts are down- the 23XX has not only a different place to check
for an interrupt, but unlike all other QLogic cards, you have to read the
status as a 32 bit word- not 16 bit words. Rather than have device specific
functions as called from the core module (in isp_intr), it makes more sense
to have the platform/bus modules do the gruntwork of splitting out the
isr, semaphore register and the first outgoing mailbox register (if needed)
*prior* to calling isp_intr (if calling isp_intr is necessary at all).