net/mlx5: Decouple PHC .adjtime and .adjphase implementations

When running a phase adjustment operation, the free running clock should
not be modified at all. The phase control keyword is intended to trigger an
internal servo on the device that will converge to the provided delta. A
free running counter cannot implement phase adjustment.

Fixes: 8e11a68e ("net/mlx5: Add adjphase function to support hardware-only offset control")
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20231114215846.5902-5-saeed@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>