sunxi: Add OrangePi PC 2 initial support

The OrangePi PC 2 is a typical SBC with the 64-bit Allwinner H5 SoC.
Add a (64-bit only) defconfig defining the required options to build
the U-Boot proper.

Create a new .dts file for it by including the (32-bit) H3 SoC .dtsi
and changing the differing components accordingly.
This is a preliminary device tree mostly for U-Boot's own sake, it
is expected to be updated once the official DT gets accepted upstream.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[squash the commits, update the commit message]
Signed-off-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/board/sunxi/MAINTAINERS b/board/sunxi/MAINTAINERS
index 2321b8b..3f21129 100644
--- a/board/sunxi/MAINTAINERS
+++ b/board/sunxi/MAINTAINERS
@@ -242,6 +242,11 @@
 S:	Maintained
 F:	configs/orangepi_zero_defconfig
 
+ORANGEPI PC 2 BOARD
+M:	Andre Przywara <andre.przywara@arm.com>
+S:	Maintained
+F:	configs/orangepi_pc2_defconfig
+
 R16 EVB PARROT BOARD
 M:	Quentin Schulz <quentin.schulz@free-electrons.com>
 S:	Maintained