ARM: EXYNOS4: register the second instance of pl330 DMAC

Platform data is provided for two instance of pl330 DMAC,
but only one DMAC is register with amba_device.
This patch register the second instance.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>