OMAP4: hwmod data: add system DMA

Add OMAP4 DMA hwmod data. In addition to original dma hwmod data,
the following changes are added.

1. DMA device attributes structure is introduced for diffenrenciating
OMAP cpu's based on DMA features.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>