ata: libahci_platform: Simplify code with for_each_child_of_node_scoped()

for_each_child_of_node_scoped() can put the device_node automatically.
So let's use it to make the code simpler by avoiding the need to
explicitly call of_node_put().

Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Link: https://lore.kernel.org/r/20240810023426.110624-1-zhangzekun11@huawei.com


Signed-off-by: Niklas Cassel <cassel@kernel.org>