mlxsw: resources: Add NVE resources

Add the following resources to be used by the NVE code:
* Number of IPv4 underlay destination IPs in a single TNUMT record
* Number of IPv6 underlay destination IPs in a single TNUMT record

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