ASoC: rsnd: fixup TDM Split mode check for CTU

Renesas sound card need to judge that whether it is using
"TDM Split mode". To judge it and for other purpose, it has
rsnd_parse_connect_simple() and rsnd_parse_connect_graph(),
but these are using different judgement policy for
TDM Split mode.
It is pointless and confusable.
This patch add new rsnd_parse_tdm_split_mode() and use common
judgement policy for simple-card/audio-graph.

Without this patch, CTU will be judged as TDM Split mode
on audio-graph card.

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