IB/mlx5: Add support for hca_core_clock and timestamp_mask

Reporting the hca_core_clock (in kHZ) and the timestamp_mask in
query_device extended verb. timestamp_mask is used by users in order
to know what is the valid range of the raw timestamps, while
hca_core_clock reports the clock frequency that is used for
timestamps.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Moshe Lazer <moshel@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>