ARM: sun6i: Define UART0 pins for A31

UART0 is the default debug/console UART on the A31.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Acked-by: NIan Campbell <ijc@hellion.org.uk>

arch/arm/include/asm/arch-sunxi/gpio.h

@@ -132,6 +132,9 @@ enum sunxi_gpio_number {
 
 #define SUN4I_GPH22_SDC1	5
 
+#define SUN6I_GPH20_UART0_TX	2
+#define SUN6I_GPH21_UART0_RX	2
+
 #define SUN4I_GPI4_SDC3		2
 
 /* GPIO pin pull-up/down config */