mlxsw: reg: Add MLXSW_REG_MPAT_SPAN_TYPE_REMOTE_ETH

Add MLXSW_REG_MPAT_SPAN_TYPE_REMOTE_ETH to support VLAN-encapsulated
port mirroring.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>