function-graph: Use comment notation for func names of dangling '}'

When a '}' does not have a matching function start, the name is printed
within parenthesis. But this makes it confusing between ending '}'
and function starts. This patch makes the function name appear in C comment
notation.

Old view:
 3)   1.281 us    |            } (might_fault)
 3)   3.620 us    |          } (filldir)
 3)   5.251 us    |        } (call_filldir)
 3)               |        call_filldir() {
 3)               |          filldir() {

New view:
 3)   1.281 us    |            } /* might_fault */
 3)   3.620 us    |          } /* filldir */
 3)   5.251 us    |        } /* call_filldir */
 3)               |        call_filldir() {
 3)               |          filldir() {
Requested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_functions_graph.c

@@ -920,7 +920,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	} else {
-		ret = trace_seq_printf(s, "} (%ps)\n", (void *)trace->func);
+		ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}