drivers/macintosh/smu.c: use for_each_child_of_node() macro

Use for_each_child_of_node() macro instead of open coding it.

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200916062122.190586-1-miaoqinglang@huawei.com
1 file changed