net: microchip: sparx5: Provide rule count, key removal and keyset select

This provides these 3 functions in the VCAP API:

- Count the number of rules in a VCAP lookup (chain)
- Remove a key from a VCAP rule
- Find the keyset that gives the smallest rule list from a list of keysets

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>