wasapi2ringbuffer: Implement GstAudioRingBuffer::pause()
WASAPI doesn't support PAUSE so it's not different from Stop().
When pipeline is in paused state, we don't need to waste CPU resource
for feeding silent buffers.
WASAPI doesn't support PAUSE so it's not different from Stop().
When pipeline is in paused state, we don't need to waste CPU resource
for feeding silent buffers.