hw/arm: add Xunlong Orange Pi PC machine

hw/arm: add Xunlong Orange Pi PC machine

The Xunlong Orange Pi PC is an Allwinner H3 System on Chip
based embedded computer with mainline support in both U-Boot
and Linux. The board comes with a Quad Core Cortex A7 @ 1.3GHz,
1GiB RAM, 100Mbit ethernet, USB, SD/MMC, USB, HDMI and
various other I/O. This commit add support for the Xunlong
Orange Pi PC machine.

Signed-off-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Tested-by: KONRAD Frederic <frederic.konrad@adacore.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 20200311221854.30370-3-nieklinnenbank@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>