add mpctl sepolicy rules for perf-hal, post_boot script

perf-hal reads these properties during initiaization and prepares
itself for the upcoming perflock requests from clients.
 - vendor.post_boot.parsed
 - ro.vendor.perf.cores_online

cleanup unused mpctl modules (like gamed, mpdecisiond)

change mpctl_prop to vendor_mpctl_prop for treble compliance

Change-Id: I34607c9d18949e88fa072c7f90862d7fdfe4a4d2