qcacld-3.0: Convert legacy channel usage

Modify the following API's code and parameter to make
sure it is using frequency instead of channel:

    wlan_hdd_validate_and_get_pre_cac_ch

Change-Id: I55ccc3fefb829bcc95e434bdc56fe630fa837bd0
CRs-Fixed: 2561857
1 file changed