ARM: mm: export default vmalloc base address

maillist inclusion
commit c3ae0029ea41f4a26a40f592062155412d1b6d07
category: feature
feature: ARM kaslr support
bugzilla: 47952
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?h=arm-kaslr-latest&id=c3ae0029ea41f4a26a40f592062155412d1b6d07



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In order for the EFI stub to be able to decide over what range to
randomize the load address of the kernel, expose the definition of
the default vmalloc base address as VMALLOC_DEFAULT_BASE.

Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Cui GaoSheng <cuigaosheng1@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>