Revert "mm/vmalloc: huge vmalloc backing pages should be split rather than compound"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6LD0S


CVE: NA

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This reverts commit 49ed1f1e.

It will have a great impact on the product if we can't use vmalloc to
alloc high-order physical pages.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>