Convert libaudiohal to Android.bp

See build/soong/README.md for more information about Soong.

USE_LEGACY_LOCAL_AUDIO_HAL isn't supported directly with this model, you
would need to change the defaults: [] line to point to the other
cc_defaults module.

Test: mmma frameworks/av/media/libaudiohal
Change-Id: I4244d085a4856232fd8230ce0663da2f3fb78a53