qcom/audio/hal: Fix ringtone playback issue on Speaker

- Start music playback on HDMI, go to settings-->sound-->ringtone
  and select a ringtone for playback. The ringtone audio playback
  starts only after 15sec.
- When ringtone is selected, the low latency path is switched from
  HDMI to Speaker device. The low latency path uses only 2 buffers
  of 10.3msec each. If the device switch takes more time, the data
  filled kernel buffers meet the stop threshold and the ALSA
  framework triggers auto stop on the stream. This results PCM
  stream to be blocked for more than 10sec and hence no audio
  heard until the write is unblocked.
- Fix the issue by setting the stop threshold to INT_MAX to avoid
  auto stop.
- This change also ensures that open_output_stream fails if the
  HDMI sink does not support 5.1 or 7.1 playback.

Bug: 8401042
Change-Id: I4c1e04be2c47d67087b1cdda87e2dce77bde58f1