scsi: qla2xxx: Fix name server relogin

Name server login is normally handle by FW. In some rare case where one
of the switches is being updated, name server login could get
affected. Trigger relogin to name server when driver detects this
condition.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>