ARM: S3C24XX: DMA resume regression fix

s3c2410_dma_suspend suspends channels from 0 to dma_channels.
s3c2410_dma_resume resumes channels in reverse order. So
pointer should be decremented instead of being incremented.

Signed-off-by: Gusakov Andrey <dron0gus@gmail.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>