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 <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

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;