I've added the .config files to contrib/uClibc-defconfigs from buildroot
to use as default configs if they are not provided in the sample.
If a particular architecture really needs an option set, it should be
either updated in the manange_uClibc_config function in
scripts/build/libc/uClibc.sh or a custom ${uclibc_name}.config should be
added to the sample (usually via `ct-ng saveconfig`).
Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>