dmaengine: ste_dma40: indicate granularity on channels

The ste_dma40 has burst level granularity on the residue
registers, which is necessary for some  clients to know,
notably the UART. Before this patch we get this message:

uart-pl011 80007000.uart: RX DMA disabled - no residue processing

This patch fixes it.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/ste_dma40.c

@@ -2838,6 +2838,7 @@ static void d40_ops_init(struct d40_base *base, struct dma_device *dev)
 	dev->device_pause = d40_pause;
 	dev->device_resume = d40_resume;
 	dev->device_terminate_all = d40_terminate_all;
+	dev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 	dev->dev = base->dev;
 }