driver/networkinterfacedriver: add wait_state()'s expected arg to step

This makes it more clear what state we're waiting for.

Signed-off-by: Bastian Krause <bst@pengutronix.de>

Author: Bastian-Krause

labgrid/driver/networkinterfacedriver.py

@@ -60,7 +60,7 @@ def configure(self, settings):
         self.proxy.configure(self.iface.ifname, settings)
 
     @Driver.check_active
-    @step()
+    @step(args=["expected"])
     def wait_state(self, expected, timeout=60):
         """Wait until the expected state is reached or the timeout expires.