ASoC: audio-graph-card2-custom-sample.dtsi: add Sample DT for Normal (Nulti)

This patch adds Normal link Multi-CPU/Codec sample to
audio-graph-card2-custom-sample.dtsi.

               +-+       +-+
        CPU1 --| | <---> | | -- Codec1
        CPU2 --| |       | | -- Codec2
               +-+       +-+

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87sfx6lu30.wl-kuninori.morimoto.gx@renesas.com


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