dmaengine: omap-dma: more consolidation of CCR register setup

We can move the handling of the DMA synchronisation control out of the
prepare functions; this can be pre-calculated when the DMA channel has
been allocated, so we don't need to duplicate this in both prepare
functions.

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>