ASoC: test-component: use new of_graph functions

Current test-component.c is using for_each_endpoint_of_node()
for parsing "port", because there was no "port" base loop before.
It has been assuming 1 port has 1 endpoint here.

But now we can use "port" base loop (= for_each_of_graph_port()).
Let's replace for_each function from "endpoint" base to "port" base.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/87h692b5sw.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>