powerpc/mm: Move vma_mmu_pagesize()

vma_mmu_pagesize() is only required for slices,
otherwise there is a generic weak version doing the
exact same thing.

Move it to slice.c
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1302e000d529c93d07208f1fae90f938e7a551b4.1649523076.git.christophe.leroy@csgroup.eu

arch/powerpc/mm/hugetlbpage.c

@@ -565,17 +565,6 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 }
 #endif
 
-unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
-{
-	/* With radix we don't use slice, so derive it from vma*/
-	if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
-		unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
-
-		return 1UL << mmu_psize_to_shift(psize);
-	}
-	return vma_kernel_pagesize(vma);
-}
-
 bool __init arch_hugetlb_valid_size(unsigned long size)
 {
 	int shift = __ffs(size);

arch/powerpc/mm/slice.c

@@ -759,4 +759,13 @@ int slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 
 	return !slice_check_range_fits(mm, maskp, addr, len);
 }
+
+unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
+{
+	/* With radix we don't use slice, so derive it from vma*/
+	if (radix_enabled())
+		return vma_kernel_pagesize(vma);
+
+	return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start));
+}
 #endif