qcacmn: Add an API to get frequency from country,chan,opclass

Add wlan regulatory API reg_country_chan_opclass_to_freq
to calculate channel frequency given country, opclass and channel
number. The API gets channel frequency from country's operating
class table by opclass and channel number pair. If the driver
can not find the pair, then try to find the frequency (MHz) by
channel number only.

Change-Id: I6a23a53e2e53e0b7c81b36f9f5c7794e9749c734
CRs-Fixed: 2605920
4 files changed