net/mlx5e: Drop priv argument of ptp function in en_fs

Both mlx5e_ptp_alloc_rx_fs and mlx5e_ptp_free_rx_fs only
make use of two priv member, pass them directly instead.
This will help dropping priv from all en_fs file.

Signed-off-by: Lama Kayal <lkayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>