dwarf-reader: relax restriction about relocation sections in try_reading_first_ksymta...

dwarf-reader: relax restriction about relocation sections in try_reading_first_ksymtab_entry

Commit 43679a610316 ("dwarf-reader: refactor
try_reading_first_ksymtab_entry_using{pre,}_v4_19_format") introduced an
assertion to ensure the absence of ksymtab relocation sections as they
are an unhandled case for try_reading_first_ksymtab_entry. This
assertion turns out to be too strict as relocation sections might be
present (e.g. on x86_64), but not affecting the functionality of this
function (i.e. helping to detect the ksymtab format). Hence, remove the
assertion and document that case.

	* src/abg-dwarf-reader.cc (try_reading_first_ksymtab_entry):
	remove assertion and update documentation

Fixes: 43679a610316 ("dwarf-reader: refactor try_reading_first_ksymtab_entry_using{pre,}_v4_19_format")
Reviewed-by: Dodji Seketeli <dodji@seketeli.org>
Signed-off-by: Matthias Maennich <maennich@google.com>