Some devices have a U-boot variant that does not accept a third
parameter on the "bootm" command, meaning we can't override the dtb
in the bootloader so have to smush it back into the kernel image
This doesn't work in QEMU but I think the problem is with the
U-Boot configuration for QEMU. It does work on at least one
hardware device so I'm pushing it anyway
Based on
https://gti.telent.net/raboof/liminix/src/branch/tftp-old-uboot
Co-authored-by: Arnout Engelen <arnout@bzzt.net>
Adding the reserved-memory node to the dtb can cause it to grow
by enough that it needs an extra page - this will overlap the start
of the kernel image if we calculate offsets based on the original size
Reported-by: sinavir
Authored-by: sinavir
new layout has rootfs followed by kernel and dtb, so that we
know the rootfs start and size to embed them into the dtb instead
of having to use dummy values and fill them in afterwards
