net/mlx5: Fix too early queueing of log timestamp work

The log timestamp work should not be queued before the command interface
is initialized, move it to a later stage in the init flow.

Fixes: 5a1023de ("net/mlx5: Add periodic update of host time to firmware")
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>