Update QCA vendor attributes for 6 GHz band support

Update QCA vendor attributes for 6 GHz band support

As a part of P802.11ax amendment, 6 GHz band operation is added.

Since the 6 GHz channel numbers are overlapping with existing 2.4 GHz
and 5 GHz channel numbers, use frequency to identify unique channel
operation instead of channel number. Channel frequency is unique across
bands.

In the existing QCA vendor interface, wherever missing, add frequency
attributes to identify unique channel operation. In addition, add
comments to document some of the previously missed attributes/values.

Note: If both channel and frequency attributes are present in vendor
command/event and
(a) If both the driver and user-space application supports 6 GHz band
then channel related attributes are deprecated and use frequency
attributes.
(b) If either driver or user-space application or both doesn't
support 6 GHz band then use channel attributes.

Signed-off-by: Rajeev Kumar Sirasanagandla <rsirasan@codeaurora.org>