ALSA: virtio: handling control messages

The control queue can be used by different parts of the driver to send
commands to the device. Control messages can be either synchronous or
asynchronous. The lifetime of a message is controlled by a reference
count.

Introduce a module parameter to set the message completion timeout:
  msg_timeout_ms [=1000]

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-4-anton.yakovlev@opensynergy.com


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