net: microchip: sparx5: Add support for getting keysets without a type id

When there is only one keyset available for a certain VCAP rule size, the
particular keyset does not need a type id when encoded in the VCAP
Hardware.

This provides support for getting a keyset from a rule, when this is the
case: only one keyset fits this rule size.

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