tracing/function: Convert func_set_flag() to a switch statement

Since the function accepts just one bit, we can use the switch
construction instead of if/else if/...

Just a cosmetic change, there should be no functional changes.
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/trace/trace_functions.c

@@ -217,10 +217,11 @@ static void tracing_stop_function_trace(void)
 
 static int func_set_flag(u32 old_flags, u32 bit, int set)
 {
-	if (bit == TRACE_FUNC_OPT_STACK) {
+	switch (bit) {
+	case TRACE_FUNC_OPT_STACK:
 		/* do nothing if already set */
 		if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
-			return 0;
+			break;
 
 		if (set) {
 			unregister_ftrace_function(&trace_ops);
@@ -230,12 +231,14 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
 			register_ftrace_function(&trace_ops);
 		}
 
-		return 0;
-	} else if (bit == TRACE_FUNC_OPT_PSTORE) {
-		return 0;
+		break;
+	case TRACE_FUNC_OPT_PSTORE:
+		break;
+	default:
+		return -EINVAL;
 	}
 
-	return -EINVAL;
+	return 0;
 }
 
 static struct tracer function_trace __read_mostly =