arm64: dts: sprd: Add support for Unisoc's UMS512

Add basic support for Unisoc's UMS512, with this patch,
the board ums512-1h10 can run into console.

Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20230306085717.420353-1-chunyan.zhang@unisoc.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>