Fix audio crackling issues due to incorrect WASAPI buffer size

(cherry picked from commit 179b078)

drivers/wasapi/audio_driver_wasapi.cpp

@@ -737,12 +737,17 @@ void AudioDriverWASAPI::thread_func(void *p_udata) {
 		ad->start_counting_ticks();
 
 		if (avail_frames > 0 && ad->audio_output.audio_client) {
+			UINT32 buffer_size;
 			UINT32 cur_frames;
 			bool invalidated = false;
-			HRESULT hr = ad->audio_output.audio_client->GetCurrentPadding(&cur_frames);
+			HRESULT hr = ad->audio_output.audio_client->GetBufferSize(&buffer_size);
+			if (hr != S_OK) {
+				ERR_PRINT("WASAPI: GetBufferSize error");
+			}
+			hr = ad->audio_output.audio_client->GetCurrentPadding(&cur_frames);
 			if (hr == S_OK) {
 				// Check how much frames are available on the WASAPI buffer
-				UINT32 write_frames = MIN(ad->buffer_frames - cur_frames, avail_frames);
+				UINT32 write_frames = MIN(buffer_size - cur_frames, avail_frames);
 				if (write_frames > 0) {
 					BYTE *buffer = nullptr;
 					hr = ad->audio_output.render_client->GetBuffer(write_frames, &buffer);