MAINTAINERS: Add missing hwmon files

Add missing documentation and header files to the hardware monitoring
subsystem section.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

MAINTAINERS

@@ -2423,7 +2423,9 @@ HARDWARE MONITORING
 L:	lm-sensors@lm-sensors.org
 W:	http://www.lm-sensors.org/
 S:	Orphan
+F:	Documentation/hwmon/
 F:	drivers/hwmon/
+F:	include/linux/hwmon*.h
 
 HARDWARE RANDOM NUMBER GENERATOR CORE
 M:	Matt Mackall <mpm@selenic.com>