Add basic DT to support Unisoc's SC9863A, with this patch,
the board sp9863a-1h10 can run into console.

Link: https://lore.kernel.org/r/20191223092948.24824-4-zhang.lyra@gmail.comSigned-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: Olof Johansson <olof@lixom.net>