restore 12000 sampling rate to audio_policy.conf

Change-Id: Ibc2589df07f79f464a7114ff57c4d79a863a16a3
drop USB audio HAL

Maybe I'm missing something but do we even have support to output
audio through USB?

Change-Id: I660d662c06c3e68f8f85fb147a2b66a63eb6d750
Merge branch 'cm-11.0' of https://github.com/Mustaavalkosta/android_device_htc_msm7x30-common into cd-4.4