wifi: mac80211: use wiphy_hrtimer_work for csa.switch_work

wifi: mac80211: use wiphy_hrtimer_work for csa.switch_work

The work item may be scheduled relatively far in the future. As the
event happens at a specific point in time, the normal timer accuracy is
not sufficient in that case.

Switch to use wiphy_hrtimer_work so that the accuracy is sufficient. To
make this work, use the same clock to store the timestamp.

CC: stable@vger.kernel.org
Fixes: ec3252bff7b6 ("wifi: mac80211: use wiphy work for channel switch")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20251028125710.68258c7e4ac4.I4ff2b2cdffbbf858bf5f08baccc7a88c4f9efe6f@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>