mm/hugetlb: Introduce hugetlb_insert_hugepage_pte[_by_pa]

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8LNGH



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Add hugetlb_insert_hugepage_pte[_by_pa] to insert hugepages into process
page table. The by_pa version performs like remap_pfn_range() that make
the pte special and can be used for reserved physical memory.

Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>