ASoC: soc-pcm: remove unneeded !rtd->dai_link check

rtd->dai_link is setuped at soc_new_pcm_runtime(),
thus "rtd->dai_link == NULL" is never happen.
This patch removes unneeded !rtd->dai_link check

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


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