ARM: S5P64X0: Move DMA support for S5P64X0

This patch moves DMA support files in the mach-s5p64x0
for S5P6440 and S5P6450 SoCs.

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: Jassi Brar <jassi.brar@samsung.com>