Fix makeinfo 5 compatibility

This is upstream 935f85422863b42b6fbca30885885e3fa28eea36.

    * ld.texinfo: Replace @ with @@ when it is part of the text.
	Correct ordering of M68HC11 entry.

	* doc/binutils.texi: Fix ordering of top level nodes.
	Replace erroneous uses of @itemx with @item.

	* bfd.texinfo: Replace @ with @@ when it is part of the text.

Conflicts:
	bfd/doc/ChangeLog
	binutils/ChangeLog
	ld/ChangeLog
	ld/ld.texinfo