serial: 8250_dma: Provide default slave configuration parameters

Some slave channel parameters will be always the same. For
example, direction for the Rx channel will always be
DMA_DEV_TO_MEM and DMA_MEM_TO_DEV for Tx channel.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dma.c

@@ -149,7 +149,13 @@ int serial8250_request_dma(struct uart_8250_port *p)
 	struct uart_8250_dma	*dma = p->dma;
 	dma_cap_mask_t		mask;
 
+	/* Default slave configuration parameters */
+	dma->rxconf.direction		= DMA_DEV_TO_MEM;
+	dma->rxconf.src_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;
 	dma->rxconf.src_addr		= p->port.mapbase + UART_RX;
+
+	dma->txconf.direction		= DMA_MEM_TO_DEV;
+	dma->txconf.dst_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;
 	dma->txconf.dst_addr		= p->port.mapbase + UART_TX;
 
 	dma_cap_zero(mask);