scripts: dts: gen_defines: redundant sorting

Removes redundant sorting of nodes.

Signed-off-by: Florian Grandel <fgrandel@code-for-humans.de>
diff --git a/scripts/dts/gen_defines.py b/scripts/dts/gen_defines.py
index 27ec689..28d4a17 100755
--- a/scripts/dts/gen_defines.py
+++ b/scripts/dts/gen_defines.py
@@ -99,14 +99,16 @@
 
         write_utils()
 
+        sorted_nodes = sorted(edt.nodes, key=lambda node: node.dep_ordinal)
+
         # populate all z_path_id first so any children references will
         # work correctly.
-        for node in sorted(edt.nodes, key=lambda node: node.dep_ordinal):
+        for node in sorted_nodes:
             node.z_path_id = node_z_path_id(node)
 
         # Check to see if we have duplicate "zephyr,memory-region" property values.
         regions = dict()
-        for node in sorted(edt.nodes, key=lambda node: node.dep_ordinal):
+        for node in sorted_nodes:
             if 'zephyr,memory-region' in node.props:
                 region = node.props['zephyr,memory-region'].val
                 if region in regions:
@@ -114,7 +116,7 @@
                              f"between {regions[region].path} and {node.path}")
                 regions[region] = node
 
-        for node in sorted(edt.nodes, key=lambda node: node.dep_ordinal):
+        for node in sorted_nodes:
             write_node_comment(node)
 
             out_comment("Node's full path:")