Pressing "R" to refresh does not update regulator and sensor values

Fix this bug, and read regulator and sensor datas again when "R"
key pressed.

Signed-off-by: Shaojie Sun <shaojie.sun@linaro.com>
diff --git a/sensor.c b/sensor.c
index bd8c354..0645d25 100644
--- a/sensor.c
+++ b/sensor.c
@@ -161,6 +161,11 @@
 	return 0;
 }
 
+static int read_sensor_info(struct tree *tree)
+{
+	return tree_for_each(tree, read_sensor_cb, NULL);
+}
+
 static int fill_sensor_cb(struct tree *t, void *data)
 {
 	struct sensor_info *sensor;
@@ -250,7 +255,7 @@
 	return ret;
 }
 
-static int sensor_display(bool refresh)
+static int sensor_print_info(struct tree *tree)
 {
 	int ret, line = 0;
 
@@ -258,13 +263,21 @@
 
 	sensor_print_header();
 
-	ret = tree_for_each(sensor_tree, sensor_display_cb, &line);
+	ret = tree_for_each(tree, sensor_display_cb, &line);
 
 	display_refresh_pad(SENSOR);
 
 	return ret;
 }
 
+static int sensor_display(bool refresh)
+{
+	if (refresh && read_sensor_info(sensor_tree))
+		return -1;
+
+	return sensor_print_info(sensor_tree);
+}
+
 static struct display_ops sensor_ops = {
 	.display = sensor_display,
 };