mm: tidy up set_ptes definition

Now that all architectures are converted, we can remove the PFN_PTE_SHIFT
ifdef and we can define set_pte_at() unconditionally.

Link: https://lkml.kernel.org/r/20230802151406.3735276-33-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Matthew Wilcox (Oracle)

include/linux/pgtable.h

@@ -204,7 +204,6 @@ static inline int pmd_young(pmd_t pmd)
 #endif
 
 #ifndef set_ptes
-#ifdef PFN_PTE_SHIFT
 /**
  * set_ptes - Map consecutive pages to a contiguous range of addresses.
  * @mm: Address space to map the pages into.
@@ -234,13 +233,8 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
 	}
 	arch_leave_lazy_mmu_mode();
 }
-#ifndef set_pte_at
-#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
-#endif
 #endif
-#else
 #define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
-#endif
 
 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 extern int ptep_set_access_flags(struct vm_area_struct *vma,