[wifi][shell] build fix

Author: mihai-ignat

src/include/platform/internal/GenericConnectivityManagerImpl_WiFi.h

@@ -81,7 +81,6 @@ class GenericConnectivityManagerImpl_WiFi
 #if CHIP_CONFIG_ENABLE_ICD_SERVER && !CHIP_DEVICE_CONFIG_ENABLE_THREAD
     CHIP_ERROR _SetPollingInterval(System::Clock::Milliseconds32 pollingInterval);
 #endif
-    CHIP_ERROR _DisconnectNetwork(void);
     static const char * _WiFiStationModeToStr(ConnectivityManager::WiFiStationMode mode);
     static const char * _WiFiAPModeToStr(ConnectivityManager::WiFiAPMode mode);
     static const char * _WiFiStationStateToStr(ConnectivityManager::WiFiStationState state);
@@ -195,12 +194,6 @@ inline CHIP_ERROR GenericConnectivityManagerImpl_WiFi<ImplClass>::_SetPollingInt
 }
 #endif
 
-template <class ImplClass>
-inline CHIP_ERROR GenericConnectivityManagerImpl_WiFi<ImplClass>::_DisconnectNetwork(void)
-{
-    return CHIP_ERROR_UNSUPPORTED_CHIP_FEATURE;
-}
-
 } // namespace Internal
 } // namespace DeviceLayer
 } // namespace chip