ftrace: build fix for ftraced_suspend

fix:

 kernel/trace/ftrace.c:1615: error: 'ftraced_suspend' undeclared (first use in this function)
 kernel/trace/ftrace.c:1615: error: (Each undeclared identifier is reported only once
 kernel/trace/ftrace.c:1615: error: for each function it appears in.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/ftrace.c

@@ -1612,7 +1612,9 @@ void ftrace_kill_atomic(void)
 {
 	ftrace_disabled = 1;
 	ftrace_enabled = 0;
+#ifdef CONFIG_DYNAMIC_FTRACE
 	ftraced_suspend = -1;
+#endif
 	clear_ftrace_function();
 }