hwmon: Add missing inclusions of <linux/jiffies.h>

Many hwmon drivers use jiffies but omit the inclusion of the header
file. Fix that, and also fix one driver which was including the header
file but didn't need it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Luca Tettamanti <kronos.it@gmail.com>
Cc: Marc Hulsman <m.hulsman@tudelft.nl>
Cc: Rudolf Marek <r.marek@assembler.cz>
diff --git a/drivers/hwmon/sht21.c b/drivers/hwmon/sht21.c
index c2565d0..5f67546 100644
--- a/drivers/hwmon/sht21.c
+++ b/drivers/hwmon/sht21.c
@@ -29,6 +29,7 @@
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/device.h>
+#include <linux/jiffies.h>
 
 /* I2C command bytes */
 #define SHT21_TRIG_T_MEASUREMENT_HM  0xe3