serial: 8250_dw: don't limit DMA support to ACPI

It should be available for DT users as well. This does not
enable DMA by default except with ACPI. DT users can enable
DMA based on a property.
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dw.c

@@ -56,11 +56,12 @@
 
 
 struct dw8250_data {
-	int		last_lcr;
-	int		last_mcr;
-	int		line;
-	struct clk	*clk;
-	u8		usr_reg;
+	u8			usr_reg;
+	int			last_lcr;
+	int			last_mcr;
+	int			line;
+	struct clk		*clk;
+	struct uart_8250_dma	dma;
 };
 
 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
@@ -241,7 +242,8 @@ static int dw8250_probe_of(struct uart_port *p,
 }
 
 #ifdef CONFIG_ACPI
-static int dw8250_probe_acpi(struct uart_8250_port *up)
+static int dw8250_probe_acpi(struct uart_8250_port *up,
+			     struct dw8250_data *data)
 {
 	const struct acpi_device_id *id;
 	struct uart_port *p = &up->port;
@@ -260,9 +262,7 @@ static int dw8250_probe_acpi(struct uart_8250_port *up)
 	if (!p->uartclk)
 		p->uartclk = (unsigned int)id->driver_data;
 
-	up->dma = devm_kzalloc(p->dev, sizeof(*up->dma), GFP_KERNEL);
-	if (!up->dma)
-		return -ENOMEM;
+	up->dma = &data->dma;
 
 	up->dma->rxconf.src_maxburst = p->fifosize / 4;
 	up->dma->txconf.dst_maxburst = p->fifosize / 4;
@@ -324,7 +324,7 @@ static int dw8250_probe(struct platform_device *pdev)
 		if (err)
 			return err;
 	} else if (ACPI_HANDLE(&pdev->dev)) {
-		err = dw8250_probe_acpi(&uart);
+		err = dw8250_probe_acpi(&uart, data);
 		if (err)
 			return err;
 	} else {