scripts: update config.sub

Latest from upstream config-patches repo. (No change to config.guess)

Signed-off-by: "David Holsgrove" <david.holsgrove@xilinx.com>
Message-Id: <f15b7c69c142e935391e.1350284600@localhost.localdomain>
Patchwork-Id: 191476

 #!/bin/sh

 set -e

 printf "Running autoconf...\n"

 autoconf -Wall --force

 printf "Done. You may now run:\n    ./configure\n"