[SCSI] BusLogic: make FlashPoint support x86-32 only

We've verified that there are 64 bit and endianness problems in the
flashpoint driver.  Reverse the logic of CONFIG_OMIT_FLASHPOINT (make
it CONFIG_SCSI_FLASHPOINT) and make it depend on X86_32 so it can't
appear for any other architectures.  Long term, if someone chooses,
they could make FlashPoint 64 bit compliant (it looks like its a
question of fixing up the sizes in some of the packed descriptors)

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>