python: Better iterate over dictionaries

In Python 2, dictionaries have 2 sets of methods to iterate over their
keys and values: keys()/values()/items() and iterkeys()/itervalues()/iteritems().

The former return lists while the latter return iterators.

Python 3 dropped the method which return lists, and renamed the methods
returning iterators to keys()/values()/items().

Using those names makes the scripts compatible with both Python 2 and 3.

Signed-off-by: Mathieu Bridon <bochecha@daitauha.fr>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

src/intel/vulkan/anv_entrypoints_gen.py

@@ -504,7 +504,7 @@ def get_entrypoints(doc, entrypoints_to_defines, start_index):
             assert e.core_version is None
             e.extensions.append(ext)
 
-    return [e for e in entrypoints.itervalues() if e.enabled]
+    return [e for e in entrypoints.values() if e.enabled]
 
 
 def get_entrypoints_defines(doc):