arch: use the newly introduced target_bits_64

Convert MIPS and Sparc over to using the new target_bits_64 variable.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

#!/bin/sh

set -e

printf "Running autoconf...\n"

autoconf -Wall --force

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