audio: Choose Speaker instead of USB Headset on force use

- getNewDevice() is selecting USB Dock Headset when user
  forces it to be speaker during VOIP/VOICE call
- Fix is to return speaker as output device in this case
CRs-Fixed: 571801

Change-Id: I81cbcef17ac6d07ac0a174e4ab35c8f5c6426257
audio: fix for unhandled NULL pointer in HAL

- Check if handle is NULL before calling pcm_close
- Check if usecase is NULL before string comparison
  operations
- Disable unnecessary debug logs in HAL

Change-Id: I569cbf510c820e1a155abf3efb4bbb525e68aafb