gen_defines: infer bindings for /zephyr,user

Tell the EDT instance that properties of the /zephyr,user node should
be generated based on the binding types inferred from the property
content.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
diff --git a/scripts/dts/gen_defines.py b/scripts/dts/gen_defines.py
index be725e4..3bf91f3 100755
--- a/scripts/dts/gen_defines.py
+++ b/scripts/dts/gen_defines.py
@@ -39,7 +39,8 @@
                          # Suppress this warning if it's suppressed in dtc
                          warn_reg_unit_address_mismatch=
                              "-Wno-simple_bus_reg" not in args.dtc_flags,
-                         default_prop_types=True)
+                         default_prop_types=True,
+                         infer_binding_for_paths=["/zephyr,user"])
     except edtlib.EDTError as e:
         sys.exit(f"devicetree error: {e}")
 
@@ -178,10 +179,16 @@
 """
 
     if node.matching_compat:
-        s += f"""
+        if node.binding_path:
+            s += f"""
 Binding (compatible = {node.matching_compat}):
   {relativize(node.binding_path)}
 """
+        else:
+            s += f"""
+Binding (compatible = {node.matching_compat}):
+  No yaml (bindings inferred from properties)
+"""
 
     s += f"\nDependency Ordinal: {node.dep_ordinal}\n"