iscsi class: fix get_host_stats error handling

iscsi_get_host_stats was dropping the error code returned
by drivers like qla4xxx.

Signed-off-by: Mike Christie <[e-mail]>
Acked-by: Vikas Chaudhary <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>

drivers/scsi/scsi_transport_iscsi.c

···
 		memset(buf, 0, host_stats_size);
 
 		err = transport->get_host_stats(shost, buf, host_stats_size);
+		if (err) {
+			kfree(skbhost_stats);
+			goto exit_host_stats;
+		}
 
 		actual_size = nlmsg_total_size(sizeof(*ev) + host_stats_size);
 		skb_trim(skbhost_stats, NLMSG_ALIGN(actual_size));