wifi: iwlwifi: mvm: add support for PTP HW clock (PHC)

Add support to enable/disable PHC clock. The PHC clock includes support
for fetching the cross timestamp i.e. a non-atomic snapshot of the current
time from the hardware (WiFi device) clock and system clock (wall-clock)
simultaneously.

Signed-off-by: Krishnanand Prabhu <krishnanand.prabhu@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230320122330.ae1d64f513b9.Ib3b6ad61c9fa2fc5908f1e0d6f59f4af6eec1a77@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>