The option should be 'net_lwip' and not 'net lwip' (see all usage of it
in the test code base).
Fixes: 2bac578c5a ("test: allow multiple config options in buildconfigspec")
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>