mlxsw: reg: Add inner packet fields to RECRv2 register

The RECRv2 register is used for setting up the router's ECMP hash
configuration. Extend it with inner packet fields to allow the ECMP hash
to be calculated based on inner flow information.

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