[SCSI] qla2xxx: Add ha->max_fibre_devices to keep track of the maximum number of targets.

Add a field to the qla_hw_data struct to allow us to set the maximum number of
fabric devices on a per adapter basis based on ISP type.

[jejb: fix up missing rval = QLA_SUCCESS to prevent uninit var warning]
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>