ARM: sunxi: Add basic A23 support

The basic blocks of the A23 are similar to the A31 (sun6i). Re-use
sun6i code for initial clock, gpio, and uart setup.

There is no SPL support for A23, as we do not have any documentation
or sample code for DRAM initialization.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4317b69..8f910f3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -456,6 +456,9 @@
 config TARGET_SUN7I
 	bool "Support sun7i"
 
+config TARGET_SUN8I
+	bool "Support sun8i"
+
 config TARGET_SNOWBALL
 	bool "Support snowball"