hal: Fix playback mute issue in pcm offload case

- Playback mute observed in direct pcm case due to compr_start fail.
- Compress write moves stream state from setup to prepared, then
  compress start moves it to running state.
- If client writes 0 bytes of data then compress write fails and hence
  compress start fails. Playback start flag is set in HAL without
  checking return value of compress start causing playback mute as
  compress start never happens.
- Fix is to set playback start flag only if compress start is success.

Change-Id: I139ddba1cd3944aefbcf02af36f8516529b0703b