net/mlx5e: TC, Move comment about mod header flag to correct place

Move the comment to the correct place where the driver actually
removes the flag and not in the check that maybe pedit actions exists.

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