hal: Configure backend with 24-bit for 24-bit playback

- For 24bit stream backend is getting configured to
  32bit which is undesirable.
- To fix this, changes are done to configure backend
  as 24bit for 24bit stream and 32bit for 32bit stream.

Change-Id: If4186d2e476c745f584903edc02818eb0af6ee12
2 files changed