samsung-a5y17lte: Init Samsung Galaxy A5 (2017)

[samueldr]

This PR adds:

• Exynos 7880 hardware description
• Exynos-specific work
• Samsung Galaxy A5 (2017) device support

The latter is done through the kernel source used for TWRP.

Additionally, patches were produced that:

• Fixes initial color channel assignation for framebuffer
• Force framebuffer on at start

Forcing the framebuffer on is weird. Though I say that, it is always weird with the current setup; it will not start in a predictable all-black state or similar, but rather it starts with a channel on, while the others are off. This ends up creating a weird blue "flash". It is not much of an issue, since in turn this gives us a working early framebuffer console.

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Tip for someone trying to know if their kernel build is fine or not: deassemble a known working boot image (e.g. TWRP), and re-assemble it using pieces from your build. (Or the other way around.) By doing so, I was able to confirm that the kernel does boot properly, and work up to the initramfs. So in my particular case the init program was failing. In addition, it allowed the console ramoops to work in that bizarro TWRP, which allowed me to confirm the error.