dtoc: Ignore the u-boot, dm-pre-reloc property

This property is not useful for of-platdata, so omit it.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/dtoc/dtoc.py

@@ -40,6 +40,7 @@ PROP_IGNORE_LIST = [
     'linux,phandle',
     "status",
     'phandle',
+    'u-boot,dm-pre-reloc',
 ]
 
 # C type declarations for the tyues we support