dtoc: Adjust code for Python 3

Update a few things in this tool so that they support Python 3:
- print statements
- iteritems()
- xrange()

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/dtoc/dtb_platdata.py b/tools/dtoc/dtb_platdata.py
index 17a3dcc..4aeeab6 100644
--- a/tools/dtoc/dtb_platdata.py
+++ b/tools/dtoc/dtb_platdata.py
@@ -449,7 +449,7 @@
                 self.out(';\n')
             self.out('};\n')
 
-        for alias, struct_name in self._aliases.iteritems():
+        for alias, struct_name in self._aliases.items():
             if alias not in sorted(structs):
                 self.out('#define %s%s %s%s\n'% (STRUCT_PREFIX, alias,
                                                  STRUCT_PREFIX, struct_name))
@@ -498,7 +498,7 @@
                         vals.append(get_value(prop.type, val))
 
                     # Put 8 values per line to avoid very long lines.
-                    for i in xrange(0, len(vals), 8):
+                    for i in range(0, len(vals), 8):
                         if i:
                             self.buf(',\n\t\t')
                         self.buf(', '.join(vals[i:i + 8]))