mlx5_en: use read sequence for gettimex64

The gettimex64() doesn't modify values in timecounter, that's why there
is no need to update sequence counter. Reduce the contention on sequence
lock for multi-thread PHC reading use-case.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241014170103.2473580-1-vadfed@meta.com


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