Make the KeyDisabler available

Add the implementation and fix up the necessary permissions

Change-Id: I5d21638a2e1a8c6a14579391261a08b4b2cd82ab
Move audio_firmware_file and /data/misc/audio entry to core sepolicy.

file_contexts uses regexes, not a globs, so use (/.*)? rather than /*
to match the directory and anything beneath it.

Since /data/misc/audio is not device-specific, move it to core sepolicy.

Consider renaming this type in the future to audio_data_file, but that
is left to a separate change as it will require a restorecon_recursive
on mako.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Change-Id: Iddc4539df686ec23edf2cf9e79e86ca353f480ce