qcacld-3.0: Clear wlan_reg_freq_to_chan

Clear wlan_reg_freq_to_chan in is_dfs_unsafe_extra_band_chan,
refine unsafe_channel_list for hdd_context to store frequency.

Change-Id: I48a75e053228b202122633a32e750f446f839ea3
CRs-Fixed: 2574028
4 files changed