mm/mremap: don't enable optimized PUD move if page table levels is 2

With two level page table don't enable move_normal_pud.

Link: https://lkml.kernel.org/r/20210616045239.370802-5-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mremap.c

@@ -276,7 +276,7 @@ static inline bool move_normal_pmd(struct vm_area_struct *vma,
 }
 #endif
 
-#ifdef CONFIG_HAVE_MOVE_PUD
+#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_HAVE_MOVE_PUD)
 static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
 		  unsigned long new_addr, pud_t *old_pud, pud_t *new_pud)
 {