Remove parallel SCSI and 1/2Gb FC support from isp(4).

This removes 288KB (36%) of the driver code and zillions of hacks and
workarounds, making single driver uniformly support several different
generations of hardware interfaces, not counting minor card variations.
After years of the hopeless fight, I don't think it worth to continue
support for hardware obsolete for 15-20 years. Instead much cleaner
now code should allow to move forward toward better locking, multiple
queues and other cool features.

All the remaining Qlogic cards starting from 4Gb 24xx to 32Gb 27xx use
the same hardware/firmware interface with minor incremental improvements,
so it seems to be a good new starting point. Except one PCI-X model all
all of them are PCIe and so still usable in modern systems.

Discussed with: ken, scottl, jpaetzel, imp
Relnotes: yes