Make the OF-compatible zImage per-board selectable. This allows the
image to only be built with the wrapper if the target actually uses it.
This fixes build-failures for the mpc85xx-p2020 subtarget.
Fixes: 557c094f0579 ("mpc85xx: only build zImage on required targets")
Signed-off-by: David Bauer <mail@david-bauer.net>
Add a universal zImage which can be loaded by mpc85xx boards at
load address 0x3000000. This allows boards to boot kernels larger than
16MB even if the image is loaded temporarily from NAND at offset
0x1000000 which some bootloaders do by default.
Signed-off-by: David Bauer <mail@david-bauer.net>
