[SCSI] qla2xxx: Add checks for a valid fcport in dev-loss-tmo/terminate_rport_io callbacks.

Commit f78badb1ae07e7f8b835ab2ea0b456ed3fc4caf4 ([SCSI] fc
transport: pre-emptively terminate i/o upon dev_loss_tmo timeout)
changed the callback semantics of dev_loss_tmo and
terminate_rport_io such that repeated calls could be made. This
could result in the the driver using stale (NULLed-out, in
dev_loss_tmo) data from the rport. Correct this by addint a
simple check to ensure a valid fcport is attached.

Signed-off-by: Seokmann Ju <[e-mail]>
Signed-off-by: Andrew Vasquez <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/qla2xxx/qla_attr.c

···
 	struct Scsi_Host *host = rport_to_shost(rport);
 	fc_port_t *fcport = *(fc_port_t **)rport->dd_data;
 
+	if (!fcport)
+		return;
+
 	qla2x00_abort_fcport_cmds(fcport);
 
 	/*
···
 qla2x00_terminate_rport_io(struct fc_rport *rport)
 {
 	fc_port_t *fcport = *(fc_port_t **)rport->dd_data;
+
+	if (!fcport)
+		return;
 
 	/*
 	 * At this point all fcport's software-states are cleared.  Perform any