tegra3common: update audio.h

-Replace QCOM_HARDWARE with ENABLE_AV_ENHANCEMENTS to ask for specific
 AV enhancements support even if it's QCOM
-Bring it inline with
 https://github.com/CyanogenMod/android_frameworks_av/commit/09dd0f0228d76be5476afbf5ffe3bfe6fd2aecdf

Change-Id: I9e12881e60ee7377bc933417f73fdf074c0cffcf
Merge "tegra3common: update audio.h" into kitkat