ASoC: audio-graph-card2: use __free(device_node) for device node

audio-graph-card2 handles many type of device_node, thus need to
use of_node_put() in many place. Let's use __free(device_node)
and avoid it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Stephen Gordon <gordoste@iinet.net.au>
Link: https://patch.msgid.link/87y0zoo5kc.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: morimoto