ctf: Import ctf.h from OpenBSD

Use it instead of the existing ctf.h from OpenSolaris. This makes it
easier to use CTF in the core kernel, and to extend the CTF format to
support wider type IDs.

The imported ctf.h is modified to depend only on _types.h, and also to
provide macros which use the "parent" bit of a type ID to refer to types
in a parent CTF container.

No functional change intended.

Reviewed by: Domagoj Stolfa, emaste
Sponsored by: The FreeBSD Foundation

(cherry picked from commit 2d5d2a986ce1a93b8567dbdf3f80bc2b545d6998)