8-byte constant is too big for long and compiler complains about this.

  lib/string.c:907:20: warning: constant 0x0101010101010101 is so big it is long

Append ULL suffix to explicitly show its type.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>