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

These drivers use IS_ERR so they should include <linux/err.h>.

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: Henrik Rydberg <rydberg@euromail.se>
diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
index c74b1d9..56dbcfb 100644
--- a/drivers/hwmon/asus_atk0110.c
+++ b/drivers/hwmon/asus_atk0110.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/dmi.h>
 #include <linux/jiffies.h>
+#include <linux/err.h>
 
 #include <acpi/acpi.h>
 #include <acpi/acpixf.h>