powerpc/mm: move FSL_BOOK3 version of update_mmu_cache()

Move FSL_BOOK3E version of update_mmu_cache() at the same
place as book3e_hugetlb_preload() as update_mmu_cache() is
the only user of book3e_hugetlb_preload().

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4d69fdc86df9c74adc71a60331a86f6afb8b5e9e.1565933217.git.christophe.leroy@c-s.fr

arch/powerpc/mm/mem.c

@@ -458,14 +458,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 	hash_preload(vma->vm_mm, address, is_exec, trap);
 }
 #endif /* CONFIG_PPC_BOOK3S */
-#if defined(CONFIG_PPC_FSL_BOOK3E) && defined(CONFIG_HUGETLB_PAGE)
-void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
-		      pte_t *ptep)
-{
-	if (is_vm_hugetlb_page(vma))
-		book3e_hugetlb_preload(vma, address, *ptep);
-}
-#endif
 
 /*
  * System memory should not be in /proc/iomem but various tools expect it