qcacld-3.0: Don't use reg_cache_channel_state

As part of regulatory cleanup,
reg_cache_channel_state is removed.

So,use reg_cache_channel_freq_state to cache
regulatory channel list instead on
reg_cache_channel_state

Also, replaced Channel Number with Channel freq
in hdd_cache_channel_info()

Change-Id: I5625b8ef4e5173d8f0d03a189ec06144a60bad6a
CRs-Fixed: 2908014
(cherry picked from commit 98af2115)