spi: spi-atmel: Use correct enum for DMA transfer direction

Use enum dma_transfer_direction as required by the functions
dmaengine_prep_slave_(sg|single)() instead of enum dma_data_direction.
This won't change behavior in practice as the enum values are
equivalent.

This fixes two warnings when building with clang:
  drivers/spi/spi-atmel.c:771:12: warning: implicit conversion from enumeration
      type 'enum dma_data_direction' to different enumeration type
      'enum dma_transfer_direction'
      [-Wenum-conversion]
                                                     DMA_FROM_DEVICE,
                                                     ^~~~~~~~~~~~~~~
  ...

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-atmel.c

@@ -768,14 +768,14 @@ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 		rxdesc = dmaengine_prep_slave_single(rxchan,
 						     as->dma_addr_rx_bbuf,
 						     xfer->len,
-						     DMA_FROM_DEVICE,
+						     DMA_DEV_TO_MEM,
 						     DMA_PREP_INTERRUPT |
 						     DMA_CTRL_ACK);
 	} else {
 		rxdesc = dmaengine_prep_slave_sg(rxchan,
 						 xfer->rx_sg.sgl,
 						 xfer->rx_sg.nents,
-						 DMA_FROM_DEVICE,
+						 DMA_DEV_TO_MEM,
 						 DMA_PREP_INTERRUPT |
 						 DMA_CTRL_ACK);
 	}
@@ -787,14 +787,14 @@ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
 		memcpy(as->addr_tx_bbuf, xfer->tx_buf, xfer->len);
 		txdesc = dmaengine_prep_slave_single(txchan,
 						     as->dma_addr_tx_bbuf,
-						     xfer->len, DMA_TO_DEVICE,
+						     xfer->len, DMA_MEM_TO_DEV,
 						     DMA_PREP_INTERRUPT |
 						     DMA_CTRL_ACK);
 	} else {
 		txdesc = dmaengine_prep_slave_sg(txchan,
 						 xfer->tx_sg.sgl,
 						 xfer->tx_sg.nents,
-						 DMA_TO_DEVICE,
+						 DMA_MEM_TO_DEV,
 						 DMA_PREP_INTERRUPT |
 						 DMA_CTRL_ACK);
 	}