ASoC: audio-graph-card2: use better image for Multi connection

1st port on Multi ports is for paired CPU/Codec, and the 2nd or later
port are for Multi Elements. This patch indicates its image to easy to
understand.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87sf5a4f1i.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>