Implementation of wifi_set_scanning_mac_oui()

wifi_set_scanning_mac_oui() accepts three bytes of MAC address
and sends the same to driver. Driver acknowledges with a
success/failure code in the return status.

Change-Id: Ic0ca3ffc452b51c123ef995b70d7efa090d76df7
CRs-Fixed: 710984
Wi-Fi HAL: Avoid excess Wi-Fi HAL logging

In WifiCommand::response_handler(), don't call Wifievent::log() which is
contributing to an excess Wi-Fi HAL logging.

Change-Id: If9e183916400ac34678257aea3bc8f190e246f1e
CRs-Fixed: 745677