qla2xxx: Restore WWPN in case of Loop Dead.

For FA-WWPN capable device, ISP2031 and ISP27XX, when loop
dead is detected by a driver, restore WWPN from NVRAM.

Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>