net/mlx5e: Remove redundant cap check for flow counter

The cap is very old and today will always exists.
The cap is not being checked anywhere else. Remove the check from
drop action when parsing tc rules in nic mode.

Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>