ARM: sunxi: Add sun8i (A23) UART0 pin mux support

UART0 pin muxes on the A23 have a different function value.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/arch/arm/include/asm/arch-sunxi/gpio.h b/arch/arm/include/asm/arch-sunxi/gpio.h
index 59122db..7e2b169 100644
--- a/arch/arm/include/asm/arch-sunxi/gpio.h
+++ b/arch/arm/include/asm/arch-sunxi/gpio.h
@@ -127,8 +127,14 @@
 #define SUNXI_GPF0_SDC0		2
 
 #define SUNXI_GPF2_SDC0		2
+
+#ifdef CONFIG_SUN8I
+#define SUNXI_GPF2_UART0_TX	3
+#define SUNXI_GPF4_UART0_RX	3
+#else
 #define SUNXI_GPF2_UART0_TX	4
 #define SUNXI_GPF4_UART0_RX	4
+#endif
 
 #define SUN4I_GPG0_SDC1		4