If SAP switch to 6 GHz channel with CSA, its channel tx power may
change like by AFC updating, so need update TPC command after CSA
complete.
Current 6 GHz channel power is got from regdb power limit, didn't
consider AFC event to update SP channel power and state. So need
to get channel power from secondary channel list which update by
AFC data.
Change-Id: I4517dd112fa6a97d5771b3d88a2587a7ae3cd4a5
CRs-Fixed: 3204221
546b59df64