proto.c: proto_registrar_dump_values(): don't skip "same name" fields.

It appears that Wireshark allows (and currently has) fields with the
same name with differing "strings" content.

Change-Id: Iddac5a2c9f456a97ea676f2007f43d786482eebd
Reviewed-on: https://code.wireshark.org/review/5491
Reviewed-by: Bill Meier <wmeier@newsguy.com>