move build dependencies to sepolicy

Some selinux build packages are defined in embedded.mk,
others are defined in system/sepolicy/Android.mk. Move all
to sepolicy as a dependency of the phony package selinux_policy
which is defined in embedded.mk.

Test: build Marlin (Treble) and Angler (non-Treble)
Change-Id: Ib0443ad3da600447fbb51f2e9f91de04dcf5f9f6
(cherry picked from commit ec6f07d6967b1828b26e8cf4580cc193c2997163)