net: microchip: sparx5: Improve VCAP admin locking in the VCAP API

This improves the VCAP cache and the VCAP rule list protection against
access from different sources.

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