[SCSI] sas: clear parent->rphy in sas_rphy_delete

We need to clear the backpointer on rphy removal, else we'll run into
problems with host removal after a device has been hot unplugged.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_transport_sas.c

@@ -697,6 +697,8 @@ sas_rphy_delete(struct sas_rphy *rphy)
 	list_del(&rphy->list);
 	spin_unlock(&sas_host->lock);
 
+	parent->rphy = NULL;
+
 	put_device(&parent->dev);
 }
 EXPORT_SYMBOL(sas_rphy_delete);