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: NChen-Yu Tsai <wens@csie.org>
Acked-by: NIan Campbell <ijc@hellion.org.uk>