For the wireless tests, CONFIG_WLAN and CONFIG_NETDEVICES are
needed, though seem to be available by default on ARCH=um, so
we didn't notice this before. Add them to fix kunit running
on other architectures.

Fixes: 28b3df1f ("kunit: add wireless unit tests")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/r/b743a5ec-3d07-4747-85e0-2fb2ef69db7c@sirena.org.uk/Signed-off-by: Johannes Berg <johannes.berg@intel.com>