dm: sunxi: Add support for serial using driver model

Add a driver for the designware serial UART used on sunxi. This just
redirects to the normal ns16550 driver.

Add a stdout-path to the device tree so that the correct UART is chosen.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 2c19ebc..8c84942 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -19,6 +19,7 @@
 obj-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
 obj-$(CONFIG_ARM_DCC) += arm_dcc.o
 obj-$(CONFIG_ATMEL_USART) += atmel_usart.o
+obj-$(CONFIG_DW_SERIAL) += serial_dw.o
 obj-$(CONFIG_LPC32XX_HSUART) += lpc32xx_hsuart.o
 obj-$(CONFIG_MCFUART) += mcfuart.o
 obj-$(CONFIG_OPENCORES_YANU) += opencores_yanu.o