rsi: regulatory enhancements

Below regulatory changes are included this patch
* Country code is saved as it will be used in bgscan.
* Region codes are mapped according to RSI region codes.
* Radar flag settings are moved under the check if 5GHZ band
  is enabled.

Signed-off-by: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Signed-off-by: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>