dmaengine: omap-dma: move CCR buffering disable errata out of the fast path

Since we record the CCR register in the dma transaction, we can move the
processing of the iframe buffering errata out of the omap_dma_start().
Move it to the preparation 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>