dmaengine: sun6i: Add cyclic capability

DMA cyclic transfers are required by audio streaming.

Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>