qcacld-3.0: Select default channel from the acs cfg list

Select the default channel from the list that the
hostpad gave instead of selecting a default channel
which can lead to discrepancy in the channels given
by the hostapd and the channel choosen for the SAP.

Bug: 149418331
Change-Id: Ib754ebdb4954607181ecea2727bca1e7cc67f39c
CRs-Fixed: 2635722