net/mlx5e: Access PHY layer counter group as other counter groups

net/mlx5e: Access PHY layer counter group as other counter groups

Adjust the way physical layer counters group is accessed to match the
generic method used for accessing other PPCNT counter groups.

Signed-off-by: Yael Chemla <ychemla@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/1742112876-2890-3-git-send-email-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>