mm/filemap: fix parameters to test_bit()

mm/filemap.c: In function 'clear_bit_unlock_is_negative_byte':
  mm/filemap.c:933:9: error: too few arguments to function 'test_bit'
    return test_bit(PG_waiters);
         ^~~~~~~~

Fixes: b91e1302ad ('mm: optimize PageWaiters bit use for unlock_page()')
Signed-off-by: Olof Johansson <olof@lixom.net>
Brown-paper-bag-by: Linus Torvalds <dummy@duh.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

@@ -930,7 +930,7 @@ static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem
 {
 	clear_bit_unlock(nr, mem);
 	/* smp_mb__after_atomic(); */
-	return test_bit(PG_waiters);
+	return test_bit(PG_waiters, mem);
 }
 
 #endif