S5P6442: DMA: Add platform devices for PL330 DMACs

Samsung's Soc S5P6442 has two PL330 DMACs. First is dedicated for
Memory->Memory data transfer while the second is meant for data
transfer with peripherals.
Define and add the peripheral PL330 DMAC as platform device on the
S5P6442 platform.

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