ASoC: Samsung: Fix build error

Fixes the following build error:
In file included from arch/arm/mach-exynos/include/mach/dma.h:24:0,
		from arch/arm/plat-samsung/include/plat/dma-ops.h:17,
		from arch/arm/plat-samsung/include/plat/dma.h:128,
		from sound/soc/samsung/pcm.c:23:
arch/arm/plat-samsung/include/plat/dma-pl330.h:106:8:
			error: redefinition of ‘struct s3c2410_dma_client’
arch/arm/plat-samsung/include/plat/dma.h:40:8: note: originally defined here
make[3]: *** [sound/soc/samsung/pcm.o] Error 1

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Sachin Kamat <sachin.kamat@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>