Merge remote-tracking branch 'remotes/kraxel/tags/audio-20200923-pull-request' into...

audio: various buffering fixes.
audio: build spiceaudio as module.

# gpg: Signature made Wed 23 Sep 2020 10:09:46 BST
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/audio-20200923-pull-request:
  audio: build spiceaudio as module
  audio: remove qemu_spice_audio_init()
  audio: run downstream playback queue unconditionally
  audio: align audio_generic_write with audio_pcm_hw_run_out
  audio: remove unnecessary calls to put_buffer_in
  audio: align audio_generic_read with audio_pcm_hw_run_in
  audio/spiceaudio: always rate limit playback stream
  audio/audio: fix video playback slowdown with spiceaudio
  audio: handle buf == NULL in put_buffer_out()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>