BUILD: sync config.guess and config.sub

The last sync with upstream for these files happened over three years ago.
My personal interest is to get support for the or1k architecture,
but there are more mainstream updates (like aarch64) in there that probably is of
interest for a more general public.

Obtained with:
wget -O config.guess 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD'
wget -O config.sub 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD'