qcacld-3.0: Fix ACS invalid defalut channel selected

If the ACS SCAN failed, the API sap_select_default_oper_chan
will select a default channel from ACS scan channel list.
At present sap_select_default_oper_chan doesn't validate the
channel with regulatory. It may select an invalid channel and
report to hostapd. This will happen when driver is doing ACS
scan, the upper layer set different country code and result to
some channels in the acs freq_list become invalid.
Fix by checking the channel supported by regulatory before select
it.

Change-Id: I438b2947ba1fd5388a2472d5122e55edc89229db
CRs-Fixed: 2723689