test: allow testing with NET_LWIP=y

Adjust network tests to run with CONFIG_NET_LWIP=y.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
diff --git a/test/py/tests/test_net.py b/test/py/tests/test_net.py
index 27cdd73..6ef02e5 100644
--- a/test/py/tests/test_net.py
+++ b/test/py/tests/test_net.py
@@ -201,7 +201,7 @@
     global net6_set_up
     net6_set_up = True
 
-@pytest.mark.buildconfigspec('net')
+@pytest.mark.buildconfigspec('net', 'net_lwip')
 def test_net_setup_static(ubman):
     """Set up a static IP configuration.