kernel: Permit overriding of KERNEL_IMAGETYPE_FOR_MAKE
Commit
a1690131691507bbf5853540229b3ad775b836bf removed the ability of
recipes to set KERNEL_IMAGETYPE_FOR_MAKE. Fix that by letting recipes
continue to set their own KERNEL_IMAGETYPE_FOR_MAKE if they so wish.
They may have been doing so for a while, and don't want to have their
carefully-selected value trampled on by kernel.bbclass.
This may be required if the recipe itself wants to build one type of
kernel, but post-process it into a different type, rather like the
vmlinux->vmlinux.gz support provided by kernel.bbclass.
Signed-off-by: Mike Crowe <mac@mcrowe.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
