um: vector: Use mac_pton() for MAC address parsing

Use mac_pton() instead of custom approach.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250506045117.1896661-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Author: btw616

arch/um/drivers/vector_kern.c

@@ -1543,21 +1543,14 @@ static void vector_timer_expire(struct timer_list *t)
 static void vector_setup_etheraddr(struct net_device *dev, char *str)
 {
 	u8 addr[ETH_ALEN];
-	char *end;
-	int i;
 
 	if (str == NULL)
 		goto random;
 
-	for (i = 0; i < 6; i++) {
-		addr[i] = simple_strtoul(str, &end, 16);
-		if ((end == str) ||
-		   ((*end != ':') && (*end != ',') && (*end != '\0'))) {
-			netdev_err(dev,
-				"Failed to parse '%s' as an ethernet address\n", str);
-			goto random;
-		}
-		str = end + 1;
+	if (!mac_pton(str, addr)) {
+		netdev_err(dev,
+			"Failed to parse '%s' as an ethernet address\n", str);
+		goto random;
 	}
 	if (is_multicast_ether_addr(addr)) {
 		netdev_err(dev,