etmem: x86: support scan hugetlb of vm

euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7RO5Q
CVE: NA
Reference: https://gitee.com/openeuler/kernel/commit/f0f2e730c851242713a3bf1e05a23170675749bd



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1. add hugetlb_entry callback to report hugetlb page.
2. try to walk host page table when ept entry is not present.
3. add SCAN_AS_HUGE to report ept page in pmd level as host
hugetlb page may be splited into 4k ept page in vm.
4. add SCAN_IGN_HOST for user to ignore access from host.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Reviewed-by: louhongxiang <louhongxiang@huawei.com>
Reviewed-by: Chen Wandun <chenwandun@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>