[SCSI] qla2xxx: Correctly handle 'global port-unavailable' AEN.

Treat a global port-unavailable PORT_UPDATE (8014h) AEN as a
loop-down event.  For this case, within the FCoE domain, the
'logical' interface has been terminated, but the driver will
not receive the classic LOOP_DOWN AEN.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>