net/mlx5: Add support for NPPS with real time mode

Add support for setting NPPS. NPPS is currently available in
REAL_TIME_CLOCK mode only. In addition allow the user to set the pulse
duration.

When NPPS pulse duration is not set explicitly by the user, driver set
it to 50% of the NPPS period.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Eran Ben Elisha <eranbe@nvidia.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>