dmaengine: at_xdmac: fix resume for cyclic transfers

When having cyclic transfers, the channel was paused when performing
suspend but was not correctly resumed.

Signed-off-by: Songjun Wu <songjun.wu@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9ee ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: <stable@vger.kernel.org> # 4.1 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>