net/mlx5: support reading device clock

net/mlx5: support reading device clock

If send schedule feature is engaged there is the Clock Queue
created, that reports reliable the current device clock counter
value. The device clock counter can be read directly from the
Clock Queue CQE.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>