net: use core MTU range checking in core net infra

geneve:
- Merge __geneve_change_mtu back into geneve_change_mtu, set max_mtu
- This one isn't quite as straight-forward as others, could use some
  closer inspection and testing

macvlan:
- set min/max_mtu

tun:
- set min/max_mtu, remove tun_net_change_mtu

vxlan:
- Merge __vxlan_change_mtu back into vxlan_change_mtu
- Set max_mtu to IP_MAX_MTU and retain dynamic MTU range checks in
  change_mtu function
- This one is also not as straight-forward and could use closer inspection
  and testing from vxlan folks

bridge:
- set max_mtu of IP_MAX_MTU and retain dynamic MTU range checks in
  change_mtu function

openvswitch:
- set min/max_mtu, remove internal_dev_change_mtu
- note: max_mtu wasn't checked previously, it's been set to 65535, which
  is the largest possible size supported

sch_teql:
- set min/max_mtu (note: max_mtu previously unchecked, used max of 65535)

macsec:
- min_mtu = 0, max_mtu = 65535

macvlan:
- min_mtu = 0, max_mtu = 65535

ntb_netdev:
- min_mtu = 0, max_mtu = 65535

veth:
- min_mtu = 68, max_mtu = 65535

8021q:
- min_mtu = 0, max_mtu = 65535

CC: [email protected]
CC: Nicolas Dichtel <[email protected]>
CC: Hannes Frederic Sowa <[email protected]>
CC: Tom Herbert <[email protected]>
CC: Daniel Borkmann <[email protected]>
CC: Alexander Duyck <[email protected]>
CC: Paolo Abeni <[email protected]>
CC: Jiri Benc <[email protected]>
CC: WANG Cong <[email protected]>
CC: Roopa Prabhu <[email protected]>
CC: Pravin B Shelar <[email protected]>
CC: Sabrina Dubroca <[email protected]>
CC: Patrick McHardy <[email protected]>
CC: Stephen Hemminger <[email protected]>
CC: Pravin Shelar <[email protected]>
CC: Maxim Krasnyansky <[email protected]>
Signed-off-by: Jarod Wilson <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

net/8021q/vlan_dev.c

@@ -826,5 +826,8 @@ void vlan_setup(struct net_device *dev)
 	dev->destructor		= vlan_dev_free;
 	dev->ethtool_ops	= &vlan_ethtool_ops;
 
+	dev->min_mtu		= 0;
+	dev->max_mtu		= ETH_MAX_MTU;
+
 	eth_zero_addr(dev->broadcast);
 }