hw: arm: Add bananapi M2-Ultra and allwinner-r40 support

hw: arm: Add bananapi M2-Ultra and allwinner-r40 support

Allwinner R40 (sun8i) SoC features a Quad-Core Cortex-A7 ARM CPU,
and a Mali400 MP2 GPU from ARM. It's also known as the Allwinner T3
for In-Car Entertainment usage, A40i and A40pro are variants that
differ in applicable temperatures range (industrial and military).

Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>