[PATCH] powerpc/kasan: Fix early region not updated correctly

[ChenJingwen]

From: Chen Jingwen <chenjingwen6 at huawei.com>

Hi, It can be reproduced with the following kernel configs.
make corenet32_smp_defconfig

CONFIG_PPC_QEMU_E500=y
CONFIG_KASAN=y
CONFIG_KASAN_GENERIC=y
CONFIG_KASAN_OUTLINE=y
# CONFIG_KASAN_INLINE is not set
CONFIG_KASAN_STACK=y
CONFIG_KASAN_VMALLOC=y

And boot the kernel with the rootfs created by buildroot-2021.08.1
qemu-system-ppc -M ppce500 -cpu e500mc -m 256 -kernel /code/linux/vmlinux \
-drive file=output/images/rootfs.ext2,if=virtio,format=raw \
-append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic

Could you help review this patch?
I will add the necessary info if any is needed.