devicetree: Add _VARGS variants to _FOREACH_ marcos

`_FOREACH_` macros do not allow the caller to pass additional arguments
to the `fn`. A series of `_VARGS` variants have been added that allow
the caller to pass arbitrary number of arguments to the `fn`:

```
DT_FOREACH_CHILD_VARGS
DT_FOREACH_CHILD_STATUS_OKAY_VARGS
DT_FOREACH_PROP_ELEM_VARGS
DT_INST_FOREACH_CHILD_VARGS
DT_INST_FOREACH_STATUS_OKAY_VARGS
DT_INST_FOREACH_PROP_ELEM_VARGS
```

Signed-off-by: Arvin Farahmand <arvinf@ip-logix.com>

scripts/dts/gen_defines.py

diff --git a/scripts/dts/gen_defines.py b/scripts/dts/gen_defines.py
index 5ce8417..435e8fe 100755
--- a/scripts/dts/gen_defines.py
+++ b/scripts/dts/gen_defines.py
@@ -479,17 +479,25 @@
             " ".join(f"fn(DT_{child.z_path_id})" for child in
                 node.children.values()))
 
+    out_dt_define(f"{node.z_path_id}_FOREACH_CHILD_VARGS(fn, ...)",
+            " ".join(f"fn(DT_{child.z_path_id}, __VA_ARGS__)" for child in
+                node.children.values()))
 
 def write_child_functions_status_okay(node):
     # Writes macro that are helpers that will call a macro/function
     # for each child node with status "okay".
 
     functions = ''
+    functions_args = ''
     for child in node.children.values():
         if child.status == "okay":
             functions = functions + f"fn(DT_{child.z_path_id}) "
+            functions_args = functions_args + f"fn(DT_{child.z_path_id}, " \
+                                                            "__VA_ARGS__) "
 
     out_dt_define(f"{node.z_path_id}_FOREACH_CHILD_STATUS_OKAY(fn)", functions)
+    out_dt_define(f"{node.z_path_id}_FOREACH_CHILD_STATUS_OKAY_VARGS(fn, ...)",
+                                                                functions_args)
 
 
 def write_status(node):
@@ -549,6 +557,11 @@
                 ' \\\n\t'.join(f'fn(DT_{node.z_path_id}, {prop_id}, {i})'
                               for i in range(len(prop.val)))
 
+            macro2val[f"{macro}_FOREACH_PROP_ELEM_VARGS(fn, ...)"] = \
+                ' \\\n\t'.join(f'fn(DT_{node.z_path_id}, {prop_id}, {i},'
+                                ' __VA_ARGS__)'
+                              for i in range(len(prop.val)))
+
         plen = prop_len(prop)
         if plen is not None:
             # DT_N_<node-id>_P_<prop-id>_LEN
@@ -749,6 +762,10 @@
             " ".join(f"fn({edt.compat2nodes[compat].index(node)})"
                      for node in okay_nodes)
 
+        for_each_macros[f"DT_FOREACH_OKAY_INST_VARGS_{ident}(fn, ...)"] = \
+            " ".join(f"fn({edt.compat2nodes[compat].index(node)}, __VA_ARGS__)"
+                     for node in okay_nodes)
+
     for compat, nodes in edt.compat2nodes.items():
         for node in nodes:
             if compat == "fixed-partitions":