Fix MAC address access in 3c507, ibmlana, pcnet32 and libertas

Commit f001fde5eadd915f4858d22ed70d7040f48767cf changed
net_device.dev_addr from a 32-byte array to a pointer.

I found 4 ethernet drivers which rely on sizeof(dev_addr), which are now
only copying 4 bytes of the address information on 32bit systems.

Fix them to use ETH_ALEN.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Reviewed-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index dcc67a3..e154677 100644
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -45,6 +45,7 @@
 #include <linux/crc32.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
+#include <linux/if_ether.h>
 #include <linux/skbuff.h>
 #include <linux/spinlock.h>
 #include <linux/moduleparam.h>
@@ -1765,7 +1766,7 @@
 
 	/* if the ethernet address is not valid, force to 00:00:00:00:00:00 */
 	if (!is_valid_ether_addr(dev->perm_addr))
-		memset(dev->dev_addr, 0, sizeof(dev->dev_addr));
+		memset(dev->dev_addr, 0, ETH_ALEN);
 
 	if (pcnet32_debug & NETIF_MSG_PROBE) {
 		printk(" %pM", dev->dev_addr);