Revert commit 25877d4e4c45451c5398aec3de50e0d5befe0e9f to add
CONFIG_OF_EMBED=y back to rpi configs so rpi3 will continue to work.
Tracked down by kettenis@
While Allwinner A64/H5 targets are built an Allwinner specific build of
ARM Trusted Firmware will need to become a build prequisite in future,
so U-Boot can build complete images after a BL31 environment variable is
set at build time with the path to a prebuilt bl31.bin.
fa4966e898