openvswitch: Add a missing break statement.

Add a break statement to prevent fall-through from
OVS_KEY_ATTR_ETHERNET to OVS_KEY_ATTR_TUNNEL.  Without the break
actions setting ethernet addresses fail to validate with log messages
complaining about invalid tunnel attributes.

Fixes: 0a6410fbde ("openvswitch: netlink: support L3 packets")
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/flow_netlink.c

@@ -2195,6 +2195,7 @@ static int validate_set(const struct nlattr *a,
 	case OVS_KEY_ATTR_ETHERNET:
 		if (mac_proto != MAC_PROTO_ETHERNET)
 			return -EINVAL;
+		break;
 
 	case OVS_KEY_ATTR_TUNNEL:
 		if (masked)