rt2x00: Add unlikely macro to special case tx status handling

This special case shouldn't happen very often. Only if a frame that
is not intended to be aggregated ends up in an AMPDU _and_ was intended
to be sent at a different MCS rate as the aggregate. Hence, using
unlikely is justified.
Signed-off-by: NHelmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -681,7 +681,7 @@ void rt2800_txdone_entry(struct queue_entry *entry, u32 status)
 	 * confuse the rate control algortihm by providing clearly wrong
 	 * data.
 	 */
-	if (aggr == 1 && ampdu == 0 && real_mcs != mcs) {
+	if (unlikely(aggr == 1 && ampdu == 0 && real_mcs != mcs)) {
 		skbdesc->tx_rate_idx = real_mcs;
 		mcs = real_mcs;
 	}