ASoC: use snd_soc_component_get_dapm()

Now we have snd_soc_component_get_dapm(),
and as soc.h say below, let's use it.

/* Don't use these, use snd_soc_component_get_dapm() */
struct snd_soc_dapm_context dapm;

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