readelf: include notes (-n) and unwind (-u) in --all/-a

This matches the GNU and LLVM versions of readelf.

As markj noted in the review -u is not actually implemented yet and has
no effect. The option is accepted and just ignored.

Reported by: andrew
Reviewed by: andrew, markj
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32003

(cherry picked from commit f161abf9f2cd7fdd28543f9774de82c89675477c)