Make secilc available

The SELinux policy compiler needs to be available on-device to compile
SELinux policy at boot on some devices. For now, we're including this
unconditionally, but, going forward, we will include this binary only
on devices which need it.

Test: Device boots -- secilc is not yet used anyway
Bug: 31363362
Change-Id: I7712b70d7c5b4c57bec2cdb44519b42d26758d09