dtoc: Fixed endianness in Prop.GetEmpty()

This should be big endian, since that is what device tree uses. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/dtoc/fdt.py b/tools/dtoc/fdt.py
index 76cd66f..ccf3b23 100644
--- a/tools/dtoc/fdt.py
+++ b/tools/dtoc/fdt.py
@@ -146,7 +146,7 @@
         if type == TYPE_BYTE:
             return chr(0)
         elif type == TYPE_INT:
-            return struct.pack('<I', 0);
+            return struct.pack('>I', 0);
         elif type == TYPE_STRING:
             return ''
         else: