ALSA: virtio: introduce device suspend/resume support

All running PCM substreams are stopped on device suspend and restarted
on device resume.

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-10-anton.yakovlev@opensynergy.com


Signed-off-by: Takashi Iwai <tiwai@suse.de>