ASoC: remove unneeded .pcm_new/free

commit ef050bec

 ("ASoC: Remove platform code now everything is
componentised") removed platform code, but it didn't remove
.pcm_new/free which existed only for platform.
This patch remove these

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>