powerpc/85xx/dts: add third elo3 dma component

Add elo3-dma-2.dtsi to support the third DMA controller.
This is used on T2080, T4240, B4860, etc.

FSL MPIC v4.3 adds a new discontiguous address range for internal interrupts,
e.g. internal interrupt 0 is at offset 0x200 and thus interrupt number is:
0x200 >> 5 = 16 in the device tree.  DMA controller 3 channel 0 internal
interrupt 240 is at offset 0x3a00, and thus the corresponding interrupt
number is: 0x3a00 >> 5 = 464, it's similar for other 7 interrupt numbers
of DMA 3 channels.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>