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>
Dispatch keys to a device specific key handler

Injects a device key handler into the input path to handle additional
keys (as found on some docks with a hardware keyboard).

Configurable via overlay settings config_deviceKeyHandlerLib and
config_deviceKeyHandlerClass.

Change-Id: I6678c89c7530fdb1d4d516ba4f1d2c9e30ce79a4

Signed-off-by:  Paul Beeler <sparksco@gmail.com>