audio/winwave: previous audio buffer should be flushed

audio/winwave: previous audio buffer should be flushed

Winwave audio backend has problem with pausing and restart audio out.
Unlike other backends, Winwave pausing API does not flush audio buffer.
As a result, the previous audio data are played in front of
user expected sound when user restart audio.
So changes it to waveOutReset()

Signed-off-by: Munkyu Im <munkyu.im@samsung.com>
Signed-off-by: malc <av1474@comtv.ru>
(cherry picked from commit 13ef70f64e9e4d7583fbd9918d8ea76194023d37)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>