libstagefright: conditionally expose support for QCOM HW AAC decoder

Change-Id: Ifcbd89ef5cf84c18e53fc16abc53b9b807f73eb2
Fix typo

Change-Id: I40b5e5c2aaba23f127d768a61dafccba048a45b4
Merge remote-tracking branch 'cyanogen/cm-10.2' into cm-10.2