audio_policy: add 48kHz to primary output

Maybe fixes this:
W/AudioTrack( 1890): AUDIO_OUTPUT_FLAG_FAST denied by client due to mismatching sample rate (48000 vs 44100)

Change-Id: Ie30a31535224db81bc68f4d7add31bcb8d0ff84f
Merge branch 'cm-11.0' of https://github.com/AceEnablementProject/android_device_htc_msm7x30-common into cd-4.4