bgmac: validate (and random if needed) MAC addr

This adds check for a valid Ethernet MAC address and in case it is not,
it will generate a valid random one, such that the adapter is still
usable.

Signed-off-by: Rafał Miłecki <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/broadcom/bgmac.c

···
 		return -ENOTSUPP;
 	}
 
+	if (!is_valid_ether_addr(mac)) {
+		dev_err(&core->dev, "Invalid MAC addr: %pM\n", mac);
+		eth_random_addr(mac);
+		dev_warn(&core->dev, "Using random MAC: %pM\n", mac);
+	}
+
 	/* Allocation and references */
 	net_dev = alloc_etherdev(sizeof(*bgmac));
 	if (!net_dev)