videostrong-kii-pro: Initial support for the Videostrong KII Pro.

Initial support for the Meson GXBB-based Videostrong KII Pro TV Box (Amlogic S905). Not to be confused with the Mecool KII Pro, which uses a different SoC (the Amlogic S905D).

The Videostrong KII Pro needs a kernel with a configuration different from the mainline kernel configuration Alpine Linux uses.

This is also my first MR, so don't hesitate to give me recommendations!

What works:

• U-Boot v2020.07 (newer versions partially work)
• mainline Linux
• booting up postmarketOS with both the vendor U-Boot (~2015) and the mainline U-Boot
• hardware acceleration
• wayland and X11 (the latter needs a config file)
• Xwayland
• ethernet (when booting from the mainline U-Boot)
• the 2 LEDs the device has
• HDMI
• USB-A
• Wi-Fi with nonfree firmware
• bluetooth with nonfree firmware
• audio
• ... (see wiki)

What doesn't work/Isn't tested: Everything else

Wiki: https://wiki.postmarketos.org/wiki/VideoStrong_KII_Pro_(videostrong-kii-pro)