mac80211: use compare_ether_addr on MAC addresses instead of memcmp

Because of the constant size and guaranteed 16 bit alignment, the inline
compare_ether_addr function is much cheaper than calling memcmp.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 9270771..a9d7235 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/if_arp.h>
+#include <linux/etherdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/pm_qos.h>
 #include <net/sch_generic.h>
@@ -176,7 +177,7 @@
 	presp = ieee80211_is_probe_resp(fc);
 	if (presp) {
 		/* ignore ProbeResp to foreign address */
-		if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
+		if (compare_ether_addr(mgmt->da, sdata->vif.addr))
 			return RX_DROP_MONITOR;
 
 		presp = true;