Call of_node_put(platform_node) to avoid refcount leak in
the error path.
Fixes: 94319ba10eca ("ASoC: mediatek: Use platform_of_node for machine drivers")
Fixes: 493433785df0 ("ASoC: mediatek: mt8173: fix device_node leak")
Signed-off-by: Miaoqian Lin <linmq006@xxxxxxxxx>