staging: ozwpan: fix memcmp() test in oz_set_active_pd()

"addr" is a pointer so it's either 4 or 8 bytes, but actually we want
to compare 6 bytes (ETH_ALEN).

As network stack already provides helper function
is_zero_ether_addr() we use that instead of memcmp

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Rupesh Gujare <rgujare@ozmodevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ozwpan/ozcdev.c

@@ -8,6 +8,7 @@
 #include <linux/cdev.h>
 #include <linux/uaccess.h>
 #include <linux/netdevice.h>
+#include <linux/etherdevice.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include "ozconfig.h"
@@ -213,7 +214,7 @@ static int oz_set_active_pd(u8 *addr)
 		if (old_pd)
 			oz_pd_put(old_pd);
 	} else {
-		if (!memcmp(addr, "\0\0\0\0\0\0", sizeof(addr))) {
+		if (is_zero_ether_addr(addr)) {
 			spin_lock_bh(&g_cdev.lock);
 			pd = g_cdev.active_pd;
 			g_cdev.active_pd = 0;