ioat3: cleanup, don't enable DCA completion writes

We already disallow raid operations while DCA is globally enabled, so
having it locally enabled is a nop and confusing when reading the code.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/ioat/dma_v3.c

@@ -334,8 +334,7 @@ static void ioat3_cleanup_tasklet(unsigned long data)
 	struct ioat2_dma_chan *ioat = (void *) data;
 
 	ioat3_cleanup(ioat);
-	writew(IOAT_CHANCTRL_RUN | IOAT3_CHANCTRL_COMPL_DCA_EN,
-	       ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
+	writew(IOAT_CHANCTRL_RUN, ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
 }
 
 static void ioat3_restart_channel(struct ioat2_dma_chan *ioat)