pinctrl: k210: call of_node_put()

pinctrl: k210: call of_node_put()

Since for_each_available_child_of_node() will increase the refcount of
node, we need to call of_node_put() manually when breaking out of the
iteration.

Fixes: d4c34d09ab03 ("pinctrl: Add RISC-V Canaan Kendryte K210 FPIOA driver")
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20221122075853.2496680-1-zhangpeng362@huawei.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>