wifi: Prevent returning an invalid factory MAC address

This is the same error checking already done in wifi_ap_iface.cpp

Change-Id: I2183e6ec13a15141dc638dc8d68fda6b3afa5aa4
diff --git a/wifi/1.4/default/wifi_sta_iface.cpp b/wifi/1.4/default/wifi_sta_iface.cpp
index 49f383a..bc6701d 100644
--- a/wifi/1.4/default/wifi_sta_iface.cpp
+++ b/wifi/1.4/default/wifi_sta_iface.cpp
@@ -636,6 +636,10 @@
 WifiStaIface::getFactoryMacAddressInternal() {
     std::array<uint8_t, 6> mac =
         iface_util_.lock()->getFactoryMacAddress(ifname_);
+    if (mac[0] == 0 && mac[1] == 0 && mac[2] == 0 && mac[3] == 0 &&
+        mac[4] == 0 && mac[5] == 0) {
+        return {createWifiStatus(WifiStatusCode::ERROR_UNKNOWN), mac};
+    }
     return {createWifiStatus(WifiStatusCode::SUCCESS), mac};
 }