x86/mm: Drop pud_mknotpresent()

There is an inconsistency between PMD and PUD-based THP page table helpers
like the following, as pud_present() does not test for _PAGE_PSE.

pmd_present(pmd_mknotpresent(pmd)) : True
pud_present(pud_mknotpresent(pud)) : False

Drop pud_mknotpresent() as there are no current users. If/when needed
back later, pud_present() will also have to be fixed to accommodate
_PAGE_PSE.

Signed-off-by: Anshuman Khandual <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Acked-by: Balbir Singh <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: Anshuman Khandual

arch/x86/include/asm/pgtable.h

@@ -595,12 +595,6 @@ static inline pmd_t pmd_mknotpresent(pmd_t pmd)
 		      __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
 }
 
-static inline pud_t pud_mknotpresent(pud_t pud)
-{
-	return pfn_pud(pud_pfn(pud),
-	      __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
-}
-
 static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)