dmaengine: at_xdmac: fix semicolon.cocci warnings

drivers/dma/at_xdmac.c:702:3-4: Unneeded semicolon

 Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>