dmaengine: omap-dma: consolidate setup of CCR

Consolidate the setup of the channel control register.  Prepare the
basic value in the preparation of the DMA descriptor, and write it into
the register upon descriptor execution.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>