mlxsw: Save EtherType as part of mlxsw_sp_nve_params

Add EtherType field to mlxsw_sp_nve_params struct.
Set it when VxLAN device is added to bridge device.

This field is needed to configure which EtherType will be used when
VLAN is pushed at ingress of the tunnel port.

Use ETH_P_8021Q for tunnel port enslaved to 802.1d and 802.1q bridges.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>