ieee802154: fix error return code in ieee802154_add_iface()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: be51da0f ("ieee802154: Stop using NLA_PUT*().")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210508062517.2574-1-thunder.leizhen@huawei.comSigned-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

net/ieee802154/nl-phy.c

@@ -241,8 +241,10 @@ int ieee802154_add_iface(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	if (nla_put_string(msg, IEEE802154_ATTR_PHY_NAME, wpan_phy_name(phy)) ||
-	    nla_put_string(msg, IEEE802154_ATTR_DEV_NAME, dev->name))
+	    nla_put_string(msg, IEEE802154_ATTR_DEV_NAME, dev->name)) {
+		rc = -EMSGSIZE;
 		goto nla_put_failure;
+	}
 	dev_put(dev);
 
 	wpan_phy_put(phy);