wifi: iwlwifi: mld: refactor AP power type setting

wifi: iwlwifi: mld: refactor AP power type setting

Fix unsafe power type mapping for iwl_txpower_constraints_cmd
that breaks if enum values change. Replace "power_type - 1" with
explicit case handling for each power type.
While on it, Add debug logging to show configured power type.

Signed-off-by: Pagadala Yesu Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20251110150012.f3b15566dac8.I31b900ab161fb627158dc1b3e2fc4ab35d84fddf@changeid