x86/kprobes: Fix typo transferred from Intel manual

x86/kprobes: Fix typo transferred from Intel manual

The arch/x86/lib/x86-opcode-map.txt file [used by the
kprobes instruction decoder] contains the line:

  af: SCAS/W/D/Q rAX,Xv

This is what the Intel manuals show, but it's not correct.
The 'X' stands for:

  Memory addressed by the DS:rSI register pair (for example, MOVS, CMPS, OUTS, or LODS).

On the other hand 'Y' means (also see the ae byte entry for
SCASB):

  Memory addressed by the ES:rDI register pair (for example, MOVS, CMPS, INS, STOS, or SCAS).

Signed-off-by: Ulrich Drepper <drepper@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/CAOPLpQfytPyDEBF1Hbkpo7ovUerEsstVGxBr%3DEpDL-BKEMaqLA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>