WASAPI: Add PaWaspi_GetIMMDevice function

The IMMDevice pointer enables access to audio device capabiltiies not exposed by PortAudio.
https://docs.microsoft.com/en-us/windows/win32/api/mmdeviceapi/nn-mmdeviceapi-immdevice

src/hostapi/wasapi/pa_win_wasapi.c

@@ -2614,6 +2614,27 @@ int PaWasapi_GetDeviceRole( PaDeviceIndex device )
     return paWasapi->devInfo[ index ].formFactor;
 }
 
+// ------------------------------------------------------------------------------------------
+int PaWasapi_GetIMMDevice( PaDeviceIndex device, void **pIMMDevice )
+{
+        PaError ret;
+        PaDeviceIndex index;
+
+        PaWasapiHostApiRepresentation *paWasapi = _GetHostApi(&ret);
+        if (paWasapi == NULL)
+                return paNotInitialized;
+
+        ret = PaUtil_DeviceIndexToHostApiDeviceIndex(&index, device, &paWasapi->inheritedHostApiRep);
+        if (ret != paNoError)
+                return ret;
+
+        if ((UINT32)index >= paWasapi->deviceCount)
+                return paInvalidDevice;
+
+        *pIMMDevice = paWasapi->devInfo[ index ].device;
+        return paNoError;
+}
+
 // ------------------------------------------------------------------------------------------
 PaError PaWasapi_GetFramesPerHostBuffer( PaStream *pStream, unsigned int *pInput, unsigned int *pOutput )
 {