bnx2fc: Add driver tunables.

Per customer request, add the following driver tunables:

o devloss_tmo
o max_luns
o queue_depth
o tm_timeout

tm_timeout is set per scsi_host in /sys/class/scsi_host/hostX/tm_timeout.

Signed-off-by: Joe Carnuccio <joe.carnuccio@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>