sepolicy: Append mm-pp-daemon path in file_contexts

Currently mm-pp-daemon path in file_contexts is
system/vendor/bin/mm-pp-daemon. Add 'system/bin/mm-pp-daemon'
path also to file_contexts for backward compatibility for
those targets where the mm-pp-daemon resides in system/bin.

Change-Id: Ic97da2042041d85ae5eb99d63f485ee5f0a0cc48