drivers/net: use is_zero_ether_addr() instead of memcmp()

Using is_zero_ether_addr() instead of directly use
memcmp() to determine if the ethernet address is all
zeros.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/hostap/hostap_info.c

@@ -4,6 +4,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/export.h>
+#include <linux/etherdevice.h>
 #include "hostap_wlan.h"
 #include "hostap.h"
 #include "hostap_ap.h"
@@ -463,8 +464,7 @@ static void handle_info_queue_scanresults(local_info_t *local)
 		prism2_host_roaming(local);
 
 	if (local->host_roaming == 2 && local->iw_mode == IW_MODE_INFRA &&
-	    memcmp(local->preferred_ap, "\x00\x00\x00\x00\x00\x00",
-		   ETH_ALEN) != 0) {
+	    !is_zero_ether_addr(local->preferred_ap)) {
 		/*
 		 * Firmware seems to be getting into odd state in host_roaming
 		 * mode 2 when hostscan is used without join command, so try