Make buildinfo_prop a regular module

Singleton modules have the capability to do a lot more than regular
modules, which is often problematic for incremental builds.
buildinfo_prop wasn't using those capabilities, so make it a regular
module type to prove it.

Bug: 332733525
Test: m out/target/product/emu64x/obj/ETC/buildinfo.prop_intermediates/buildinfo.prop
Change-Id: I288bf2fd4727a17ff299272d4cfcc611e064c55a