Noted recently that, while physical devices have lro disabled when
attached to a bridge, vlan devices do not.  This is because the vlan netdev has
no get/set flags method in its ethtool_ops struct. This series teaches
dev_disable_lro to recognize vlan interfaces and operate on the underlying
physical device instead.

Change notes:
v2) Rewrite of my origional solution As per Ben H.- instead of passing ethtool
command from the vlan device to the physical device, instead teach
dev_disable_lro to recognize vlans and operate on the underlying physical device
directly.  This lets us avoid the various oddities of operating with ethtool on
a vlan device, and is more consice to boot.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: davem@davemloft.net
CC: bhutchings@solarflare.com