net: dsa: ocelot: Simplify with scoped for each OF child loop

Use scoped for_each_available_child_of_node_scoped() when iterating over
device nodes to make code a bit simpler.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20240820074805.680674-1-ruanjinjie@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>