dtoc: make ScanTree recurse into subnodes

Previously, dtoc could only process the top-level nodes which led to
device nodes in hierarchical trees to be ignored. E.g. the mmc0 node
in the following example would be ignored, as only the soc node was
processed:

  / {
	soc {
		mmc0 {
			/* ... */
		};
	};
  };

This introduces a recursive helper method ScanNode, which is used by
ScanTree to recursively parse the entire tree hierarchy.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/dtoc/dtoc.py

@@ -172,6 +172,21 @@ class DtbPlatdata:
         """
         self.fdt = fdt_select.FdtScan(self._dtb_fname)
 
+    def ScanNode(self, root):
+        for node in root.subnodes:
+            if 'compatible' in node.props:
+                status = node.props.get('status')
+                if (not options.include_disabled and not status or
+                    status.value != 'disabled'):
+                    self._valid_nodes.append(node)
+                    phandle_prop = node.props.get('phandle')
+                    if phandle_prop:
+                        phandle = phandle_prop.GetPhandle()
+                        self._phandle_node[phandle] = node
+
+            # recurse to handle any subnodes
+            self.ScanNode(node);
+
     def ScanTree(self):
         """Scan the device tree for useful information
 
@@ -180,8 +195,10 @@ class DtbPlatdata:
             _valid_nodes: A list of nodes we wish to consider include in the
                 platform data
         """
-        node_list = []
         self._phandle_node = {}
+        self._valid_nodes = []
+        return self.ScanNode(self.fdt.GetRoot());
+
         for node in self.fdt.GetRoot().subnodes:
             if 'compatible' in node.props:
                 status = node.props.get('status')