x86: Add verbose option to insn decoder test

Add verbose option to insn decoder test. This dumps decoded
instruction when building kernel with V=1.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
LKML-Reference: <20091116230618.5250.18762.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>