scsi: qla2xxx: Use BIT_6 to acquire FAWWPN from switch

scsi: qla2xxx: Use BIT_6 to acquire FAWWPN from switch

If FA-WWPN feature disabled on the switch side and enabled for the
adapter, then driver would update the port name with switch port name.

This patch fixes issue by checking correct BIT flag to validate.

Fixes: 41dc529a4602 ("qla2xxx: Improve RSCN handling in driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sawan Chandak <sawan.chandak@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>