ASoC: audio-graph-card: tidyup define position

commit f986907c ("ASoC: audio-graph-card: add widgets and routing for
external amplifier support") added new function
asoc_graph_card_outdrv_event(), but the inserted position breaks
define area. This patch tidyup it

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>