[rdk-b][mt7986][wifi-hal][Add getRadioPossibleChannels]

[Description]
Add getRadioPossibleChannels
1. Use iw instead of iwlist
2. Add a check of dfs enable. If dfs is disable, the function should ignore dfs channels.

[Release-log]
N/A

1 file changed
tree: 996375f5b22fc24f829124e22d8eb99e2964c7b6
  1. src/