iommu: pass cell_count = -1 to of_for_each_phandle with cells_name

Currently of_for_each_phandle ignores the cell_count parameter when a
cells_name is given. I intend to change that and let the iterator fall
back to a non-negative cell_count if the cells_name property is missing
in the referenced node.

To not change how existing of_for_each_phandle's users iterate, fix them
to pass cell_count = -1 when also cells_name is given which yields the
expected behaviour with and without my change.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/iommu/arm-smmu.c

@@ -333,7 +333,7 @@ static int __find_legacy_master_phandle(struct device *dev, void *data)
 	int err;
 
 	of_for_each_phandle(it, err, dev->of_node, "mmu-masters",
-			    "#stream-id-cells", 0)
+			    "#stream-id-cells", -1)
 		if (it->node == np) {
 			*(void **)data = dev;
 			return 1;

drivers/iommu/mtk_iommu_v1.c

@@ -426,7 +426,7 @@ static int mtk_iommu_add_device(struct device *dev)
 	int err;
 
 	of_for_each_phandle(&it, err, dev->of_node, "iommus",
-			"#iommu-cells", 0) {
+			"#iommu-cells", -1) {
 		int count = of_phandle_iterator_args(&it, iommu_spec.args,
 					MAX_PHANDLE_ARGS);
 		iommu_spec.np = of_node_get(it.node);