kitakami-common: Remove WIFI_HIDL_FEATURE_DISABLE_AP_MAC_RANDOMIZATION

* Resolved the following warning:

`hardware/interfaces/wifi/1.4/default/wifi_feature_flags.cpp:148:9: warning: WIFI_HIDL_FEATURE_DISABLE_AP_MAC_RANDOMIZATION is deprecated; override 'config_wifi_ap_randomization_supported' in frameworks/base/core/res/res/values/config.xml in the device overlay instead [-W#pragma-messages]`

* Additionally, it seems that with this feature explicitly disabled,
  tethering fails to start.

Change-Id: I67916f4251b191a3c5a331df795c4d3ff58431f8