The MFIFO is shared by all channels so restrict each memcpy to it's fair
share. This is being over cautious, but without a global view of DMA
channel usage on a system it's not possible to come up with a more
optimum safe limit.
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>