ascend: vmalloc: export new function for share pool

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4EUVI


CVE: NA

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This is a prepare patch for share pool, export new function
to vmalloc hugepage and vmap the hugepage to virtually
contiguous space.

The new head file share_pool.h is mainly used for share pool
features and export some sp_xxx function when ascend_share_pool
config is enabled, and do nothing by default.

Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Signed-off-by: Li Ming <limingming.li@huawei.com>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>