ACPI: update thermal temperature

Fix the problem that thermal_get_temp returns the cached value,
which causes the temperature in generic thermal never updates.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 5e9641c..782c225 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -884,10 +884,15 @@
 static int thermal_get_temp(struct thermal_zone_device *thermal, char *buf)
 {
 	struct acpi_thermal *tz = thermal->devdata;
+	int result;
 
 	if (!tz)
 		return -EINVAL;
 
+	result = acpi_thermal_get_temperature(tz);
+	if (result)
+		return result;
+
 	return sprintf(buf, "%ld\n", KELVIN_TO_MILLICELSIUS(tz->temperature));
 }