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/drivers/power/domain/power-domain-uclass.c b/drivers/power/domain/power-domain-uclass.c
index c2c7c3b..af829db 100644
--- a/drivers/power/domain/power-domain-uclass.c
+++ b/drivers/power/domain/power-domain-uclass.c
@@ -117,7 +117,7 @@
 	int i, count, ret = 0;
 
 	count = dev_count_phandle_with_args(dev, "power-domains",
-					    "#power-domain-cells");
+					    "#power-domain-cells", 0);
 	for (i = 0; i < count; i++) {
 		ret = power_domain_get_by_index(dev, &pd, i);
 		if (ret)