common/sfc_efx/base: refine adding count action to set

common/sfc_efx/base: refine adding count action to set

1) Invalid counter ID is always set by default.
   Do not set it again when adding the action.

2) Counter ID validity check is missing in the
   action set allocation helper. Introduce it.

Fixes: 238306cf9aff ("common/sfc_efx/base: support counter in action set")
Cc: stable@dpdk.org
Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>