mm-introduce-mm_find_pmd-fix

mm-introduce-mm_find_pmd-fix

mm/rmap.c: In function 'try_to_unmap_cluster':
mm/rmap.c:1364:9: warning: unused variable 'pud' [-Wunused-variable]
mm/rmap.c:1363:9: warning: unused variable 'pgd' [-Wunused-variable]

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>