[SCSI] libsas: continue revalidation

Continue running revalidation until no more broadcast devices are
discovered. Fixes cases where re-discovery completes too early in a
domain with multiple expanders with pending re-discovery events.
Servicing BCNs can get backed up behind error recovery.

Cc: <[e-mail]>
Signed-off-by: Dan Williams <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/libsas/sas_expander.c

···
 	struct domain_device *dev = NULL;
 
 	res = sas_find_bcast_dev(port_dev, &dev);
-	if (res)
-		goto out;
-	if (dev) {
+	while (res == 0 && dev) {
 		struct expander_device *ex = &dev->ex_dev;
 		int i = 0, phy_id;
 
···
 			res = sas_rediscover(dev, phy_id);
 			i = phy_id + 1;
 		} while (i < ex->num_phys);
+
+		dev = NULL;
+		res = sas_find_bcast_dev(port_dev, &dev);
 	}
-out:
 	return res;
 }