dmaengine: dw-edma: Change DMA abbreviation from lower into upper case

To keep code consistent, some comments with dma keyword written in lower
case are now in upper case.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/8c4b3db90767972a2b4cbb6fa818cf0e9c3d6fe3.1613674948.git.gustavo.pimentel@synopsys.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/dw-edma/dw-edma-core.c

@@ -341,15 +341,15 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		return NULL;
 
 	switch (chan->config.direction) {
-	case DMA_DEV_TO_MEM: /* local dma */
+	case DMA_DEV_TO_MEM: /* local DMA */
 		if (dir == DMA_DEV_TO_MEM && chan->dir == EDMA_DIR_READ)
 			break;
 		return NULL;
-	case DMA_MEM_TO_DEV: /* local dma */
+	case DMA_MEM_TO_DEV: /* local DMA */
 		if (dir == DMA_MEM_TO_DEV && chan->dir == EDMA_DIR_WRITE)
 			break;
 		return NULL;
-	default: /* remote dma */
+	default: /* remote DMA */
 		if (dir == DMA_MEM_TO_DEV && chan->dir == EDMA_DIR_READ)
 			break;
 		if (dir == DMA_DEV_TO_MEM && chan->dir == EDMA_DIR_WRITE)