S5P6440: DMA: Add platform devices for PL330 DMACs

Samsung's Soc S5P6440 has one PL330 DMAC.
Define and add the PL330 DMAC as platform device on the
S5P6440 platform.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>