Same as the commit 518de86b (ASoC: tegra: register 'platform' from DAIs,
get rid of pdev), it makes mxs-pcm not a platform_driver but helper to
register "platform", so that the platform_device for mxs-pcm can be
saved completely.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>