BoardConfigCommon: clean-up deprecated variable in 4.2

Change-Id: I4406bba603a4c6d064c3d5aac50861714e52c692
BoardConfigCommon: use variant
audio: CyanogenMod/android_hardware_qcom_audio-caf
display: Xperia2011/android_hardware_qcom_display-legacy

Change-Id: I9a7804a46a674588c22f046e4268bcdbaca29834
Headers: update & clean-up unused in 4.2

Change-Id: I026869283f73e04c4a58bbb8f41c94a7afa7ee29