Mixtile Blade 3 refactor / rockchip-rk3588 edge 6.7

• mixtile-blade3: enable edge branch with new dt; all branches use vendor u-boot

• mixtile-blade3 / rockchip-rk3588-edge 6.7: enable tsadc for thermal sensors

• mixtile-blade3 / rockchip-rk3588 edge 6.7: slow down eMMC from hs400 to hs200

• mixtile-blade3 / rockchip-rk3588 edge 6.7: pci3x4 for Mixtile Blade3 (rpardini's bad take)

• mixtile-blade3 / rockchip-rk3588 edge 6.7: cleanups for Mixtile Blade3

• mixtile-blade3 / rockchip-rk3588 edge 6.7: add DT (original from Joshua Riek)

https://github.com/armbian/build/pull/6096