dmaengine: at_xdmac: don't restore unsaved status

save_gs is supposed to save the channel status in order to be restored at
resume time but it is never updated and is always 0. Anyway, the channel
status is updated in the per channel loop later in the resume function.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>