Fixes a build error similar to

device/lge/iprj-common/sepolicy/file.te":8:ERROR 'duplicate declaration of type/attribute' at token ';' on line 7523:

type audio_firmware_file, file_type;
checkpolicy:  error(s) encountered while parsing configuration

This error is caused by audio_firmware_file becoming an alias of audio_data_file in the main SEPolicy.

See here for details:
https://github.com/CyanogenMod/android_external_sepolicy/commit/8bebb1c5dd10f704d0f5c90b9c51ed7f3e91eb06