Allwinner H3 framebuffer console support

[Jared McNeill <jmcneill%invisible.ca@localhost>]

Hi folks --

As part of the CHIP port, I added support for the "simplefb" DT bindings. 
This allows the kernel to take over a framebuffer setup by the bootloader.

I've just added a patch to our U-Boot to enable simplefb support for sunxi 
socs using the newer DE2 display device and added the framebuffer node to 
our sun8i-h3 dts template to activate it.

If you update your kernel and dtb, upgrade U-Boot (2017.07nb1 for 
orangepi-plus2e and orangepi-2), and plug in HDMI before powering on the 
board, you should have a working framebuffer. Serial console is 
still the default; you can override it by adding console=fb to bootargs in 
U-Boot. The usual things (Xorg etc) will work also as simplefb is built on 
top of genfb/wsfb.

Cheers,
Jared