As specified in scripts/install.sh, the priority order is as follows
(from highest to lowest):
~/bin/installkernel
/sbin/installkernel
arch/loongarch/boot/install.sh
Fallback to default install.sh if installkernel is not found.
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>