net/mlx5: Implement PTM cross timestamping support

net/mlx5: Implement PTM cross timestamping support

Expose Precision Time Measurement support through related PTP ioctl.

The performance of PTM on ConnectX-7 was evaluated using both real-time
(RTC) and free-running (FRC) clocks under traffic and no traffic
conditions. Tests with phc2sys measured the maximum offset values at a 50Hz
rate, with and without PTM.

Results:

1. No traffic
+-----+--------+--------+
|     | No-PTM | PTM    |
+-----+--------+--------+
| FRC | 125 ns | <29 ns |
+-----+--------+--------+
| RTC | 248 ns | <34 ns |
+-----+--------+--------+

2. With traffic
+-----+--------+--------+
|     | No-PTM | PTM    |
+-----+--------+--------+
| FRC | 254 ns | <40 ns |
+-----+--------+--------+
| RTC | 255 ns | <45 ns |
+-----+--------+--------+

Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Co-developed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Tested-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20240730134055.1835261-4-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>