winealsa.drv: Fix AudioRenderClient write pointer calculation.

dlls/winealsa.drv/mmdevdrv.c

@@ -2028,8 +2028,8 @@ static HRESULT WINAPI AudioRenderClient_ReleaseBuffer(
     }
 
     if(This->buf_state == LOCKED_NORMAL)
-        buffer = This->local_buffer +
-            (This->lcl_offs_frames + This->held_frames) * This->fmt->nBlockAlign;
+        buffer = This->local_buffer + This->fmt->nBlockAlign *
+          ((This->lcl_offs_frames + This->held_frames) % This->bufsize_frames);
     else
         buffer = This->tmp_buffer;