ALSA: compress: add timestamp support for compress audio

Add timestamp field to compress structure which indicates when
audio sample has been captured or needs to be rendered.

Change-Id: Ie61170c6645c71207e7df1c7176e0750e47590f8
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
Signed-off-by: Meng Wang <mwang@codeaurora.org>