pinctrl: freescale: mxs: Fix refcount of child

of_get_next_child() will increase refcount of the returned node, need
use of_node_put() on it when done.

Per current implementation, 'child' will be override by
for_each_child_of_node(np, child), so use of_get_child_count to avoid
refcount leakage.

Fixes: 17723111e64f ("pinctrl: add pinctrl-mxs support")
Signed-off-by: Peng Fan <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/freescale/pinctrl-mxs.c

···
 	int ret;
 	u32 val;
 
-	child = of_get_next_child(np, NULL);
-	if (!child) {
+	val = of_get_child_count(np);
+	if (val == 0) {
 		dev_err(&pdev->dev, "no group is defined\n");
 		return -ENOENT;
 	}