ARM: SAMSUNG: DMA Cleanup as per sparse

Function declaration differs between file: dma.c and file:dma.h
and SPARSE (Documentation/sparse.txt) gives error messages

All dma channels are members of 'enum dma_ch' and not 'unsigned int'
Please have a look at channel definitions in:
arch/arm/mach-s3c64xx/include/mach/dma.h
arch/arm/plat-samsung/include/plat/s3c-dma-pl330.h
arch/arm/mach-s3c2410/include/mach/dma.h
So all arguments should be of type 'enum dma_ch'

Signed-off-by: Sangwook Lee <sangwook.lee@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>