net: microchip: sparx5: Adding KUNIT tests of key/action values in VCAP API

This tests that the available keyfield and actionfield add methods are
doing the exepected work: adding the value (and mask) to the
keyfield/actionfield list item in the rule.

The test also covers the functionality that matches a rule to a keyset.
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>