pinctrl: freescale: mxs: Fix refcount of child

[ Upstream commit 7f500f2011c0bbb6e1cacab74b4c99222e60248e ]

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: 17723111 ("pinctrl: add pinctrl-mxs support")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/20240504-pinctrl-cleanup-v2-18-26c5f2dc1181@nxp.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>