Fix typo milivolt => millivolt

Signed-off-by: Thomas Weber <thomas@tweber.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/hwmon/wm831x b/Documentation/hwmon/wm831x
index 24f47d8..1144675 100644
--- a/Documentation/hwmon/wm831x
+++ b/Documentation/hwmon/wm831x
@@ -22,7 +22,7 @@
 Voltage Monitoring
 ------------------
 
-Voltages are sampled by a 12 bit ADC.  Voltages in milivolts are 1.465
+Voltages are sampled by a 12 bit ADC.  Voltages in millivolts are 1.465
 times the ADC value.
 
 Temperature Monitoring