net: eth: Clear MAC address in eth_pre_remove()

platdata->enetaddr was assigned to a value in dev_probe() last time.
If we don't clear it, for dev_probe() at the second time, dm eth
will end up treating it as a MAC address from ROM no matter where it
came from originally (maybe env, ROM, or even random). Fix this by
clearing platdata->enetaddr when removing an Ethernet device.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

net/eth.c

@@ -575,8 +575,13 @@ static int eth_post_probe(struct udevice *dev)
 
 static int eth_pre_remove(struct udevice *dev)
 {
+	struct eth_pdata *pdata = dev->platdata;
+
 	eth_get_ops(dev)->stop(dev);
 
+	/* clear the MAC address */
+	memset(pdata->enetaddr, 0, 6);
+
 	return 0;
 }