net/mlx5e: Generalize PTP implementation

Following patches in the set add support for RX PTP. Rename PTP prefix
from %s/port_ptp/ptp/g to include RX PTP too.

In addition rename indication (used in statistics context) that PTP-SQ
was opened: %s/port_ptp_opened/tx_ptp_opened/g. This will simplify adding
indication that PTP-RQ was opened.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>