ASoC: samsung: Trivial cleanups in header files

commit 5d229ce569be ("ASoC: samsung: move plat/ headers to local directory")
moved the header files but forgot to clean the pointers to their old locaton.
Remove them now.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>