[SCSI] qla2xxx: Reduce request queue-size overhead with recent ISPs.

The original code to 'resize request-queues' based on iocb-counts
and employed during early ISP23xx testing was too
overly-pessimistic with regards to latencies in the firmware
pulling requests.  Recent ISPs can easily keep up processing a
stream of commands from an abbreviated (effectively, half the
original size) queue.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>