ASoC: soc-pcm.c: use dai_link on soc_get_playback_capture()

ASoC: soc-pcm.c: use dai_link on soc_get_playback_capture()

soc_get_playback_capture() (A) is using rtd->dai_link->xxx everywhere.
Because of that, 1 line is unnecessarily long and not readable.

(A)	static int soc_get_playback_capture(...)
	{
		if (rtd->dai_link->dynamic ...) {
		    ^^^^^^^^^^^^^
			...
		} else {
			int cpu_capture = rtd->dai_link->c2c_params ?
					  ^^^^^^^^^^^^^
			...
		}

		if (rtd->dai_link->playback_only) {
		    ^^^^^^^^^^^^^
			...
		}
		...
	}

This patch uses variable "dai_link" to be clear code.
Nothing changes the meanings.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/87wn0qzlqp.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>