binutils: doc: move artifacts back to MAINTAINERCLEANFILES

binutils: doc: move artifacts back to MAINTAINERCLEANFILES

In commit 2b44a6a237 (" binutils: doc: make `make clean` clean more
things"), I moved the doc build artifacts to MOSTLYCLEANFILES, which
made them get removed by "make clean".

Because generating binutils.info requires makeinfo, and we do not want
to require makeinfo when building from the tarball, binutils.info should
not get removed by "make clean" (otherwise, it won't be included in the
tarball).

And to be consistent with other projects (e.g. ld and gas), we also want
to ship the built man pages in the tarball.

This patch puts back all these in MAINTAINERCLEANFILES, so that they are
bundled in the tarball, and only cleaned if you use "make
maintainer-clean".

Tested by building a source release and confirming they are present.

binutils/ChangeLog:

	PR 25491
	* doc/Makefile.am: Rename MOSTLYCLEANFILES to MAINTAINERCLEANFILES.
	* doc/Makefile.in: Re-generate.