ARM: OMAP2+: DMA: Moving OMAP2+ DMA channel definitions to mach-omap2

Similar to omap1, some of the omap2+ dma channel definitions are
used by some drivers. For moving omap2+ dma channel definitions
to mach-omap2/, the used ones should be defined locally to driver.
Drivers can eliminate it using DT, platform data, or IORESOURCE_DMA
And moving omap2+ DMA channel definitions to mach-omap2

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>