Removing init and ueventd access to generic char files

There are many character files that are unreachable to all processes
under selinux policies. Ueventd and init were the only two domains that
had access to these generic character files, but auditing proved there
was no use for that access. In light of this, access is being completely
revoked so that the device nodes can be removed, and a neverallow is
being audited to prevent future regressions.

Test: The device boots
Bug: 33347297
Change-Id: If050693e5e5a65533f3d909382e40f9c6b85f61c