perf probe: Add '--demangle'/'--no-demangle'

You can't pass demangled name into "perf probe", because of special chars:
./perf probe -f -x /tmp/a.out 'foo(int)'
Semantic error :There is non-digit char in line number.

And you can't even pass without demangling (because it search symbol in
DSO with demangle=true):
./perf probe -f -x /tmp/a.out _Z3fooi
no symbols found in /tmp/a.out, maybe install a debug package?

However:
nm /tmp/a.out | grep foo
000000000040056d T _Z3fooi

After this patch, using the next command:
./perf probe -f --no-demangle -x /tmp/a.out _Z3fooi

probe will be successfully added.
Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382947464-31266-1-git-send-email-a3at.mail@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-probe.c

@@ -325,6 +325,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
 		     opt_set_filter),
 	OPT_CALLBACK('x', "exec", NULL, "executable|path",
 			"target executable name or path", opt_set_target),
+	OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle,
+		    "Disable symbol demangling"),
 	OPT_END()
 	};
 	int ret;