waf: allow for no param default support

this allows apj files to be built for example fw

Tools/ardupilotwaf/chibios.py

@@ -75,9 +75,7 @@ class set_default_parameters(Task.Task):
         sys.path.append(os.path.dirname(apj_tool))
         from apj_tool import embedded_defaults
         defaults = embedded_defaults(self.inputs[0].abspath())
-        if not defaults.find():
-            print("Error: Param defaults support not found in firmware")
-            sys.exit(1)
+        if defaults.find():
             defaults.set_file(abs_default_parameters)
             defaults.save()