wifi: ieee80211: remove unused enum ieee80211_client_reg_power

This has never been used, and it's really not directly
representing the spec, so shouldn't have been here in
the first place. Remove it.

Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240523120945.32ed8fc1522d.Id4480d162e1921478e33d145890dc16c263b57bf@changeid


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