wifi: Set the mode at native layer

 * Set normal/AP mode so that the HAL can specify correct module
   arguments when loading the driver.
 * Needed to fix wifi tethering for some devices
   https://gerrit.omnirom.org/#/c/4215/

Change-Id: Ic460f00f0308840d4875582673020786e46258f7
Merge "wifi: Set the mode at native layer" into du44