wil6210: add option to ignore OTA regulatory hints

On some platforms, the regulatory domain (country) is set
using mechanisms external to WIFI, such as cellular modem
and GPS. In these scenarios the regulatory hints that
are received over the air (in beacons and similar) can
conflict and even cause an incorrect country to be set.
Add an option to ignore the OTA regulatory hints to better
support such scenarios.

Change-Id: Ia46fe2699f4cc9859713947c0153107462fdec06
Signed-off-by: Lior David <liord@codeaurora.org>