ASoC: audio-graph-card: add link_info

Current audio-graph-card is parsing DAI link for both "normal sound" and
"DPCM sound". On this driver, it needs to count and parse
DAIs/Links/Codec Conf from each links.
Then, counting/parsing link loop are very similar, but using different
implementation. Because of this background, the link loop code is very
mysterious. Mystery code will be trouble in the future.

To preparing cleanup code, this patch adds link_info which handles
number of DAIs/Links/Codec Conf, and CPU/Codec turn.

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