dm: add cells_count parameter in *_count_phandle_with_args

The cell_count argument is required when cells_name is NULL.

This patch adds this parameter in live tree API
- of_count_phandle_with_args
- ofnode_count_phandle_with_args
- dev_count_phandle_with_args

This parameter solves issue when these API is used to count
the number of element of a cell without cell name. This parameter
allow to force the size cell.

For example:
  count = dev_count_phandle_with_args(dev, "array", NULL, 3);

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/dm/of_access.h b/include/dm/of_access.h
index 2fa65c9..cc382b1 100644
--- a/include/dm/of_access.h
+++ b/include/dm/of_access.h
@@ -450,6 +450,7 @@
  * @np:		pointer to a device tree node containing a list
  * @list_name:	property name that contains a list
  * @cells_name:	property name that specifies phandles' arguments count
+ * @cells_count: Cell count to use if @cells_name is NULL
  * @return number of phandle found, -ENOENT if
  *	@list_name does not exist, -EINVAL if a phandle was not found,
  *	@cells_name could not be found, the arguments were truncated or there
@@ -460,7 +461,8 @@
  *
  */
 int of_count_phandle_with_args(const struct device_node *np,
-			       const char *list_name, const char *cells_name);
+			       const char *list_name, const char *cells_name,
+			       int cells_count);
 
 /**
  * of_alias_scan() - Scan all properties of the 'aliases' node