Wi-Fi: Pass default country code to driver

This patch reverts partially the change http://review.cyanogenmod.org/#/c/28918/8, and
passing the default country code ("GB") to the driver instead of null.

Change-Id: I7d7115155a0a52261931ffaddaf35f316d095800
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
fixes to make wifi priority work

Change-Id: Ia2832f8469808975ddd5d0f5104f9b9dc9ef6f9c