[SCSI] qla2xxx: Do not honour max_vports from firmware for 2G ISPs and below.

For 23XX ISPs, max_vports may return an invalid value.
Do not honour it.

Cc: Stable Tree <stable@kernel.org>
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>