hwmon: Update documentation on fan_max

Add fan_max description.

Add fan limit alarm 'max_alarm' to the alarm section.
Signed-off-by: NChristian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Documentation/hwmon/sysfs-interface

@@ -150,6 +150,11 @@ fan[1-*]_min	Fan minimum value
 		Unit: revolution/min (RPM)
 		RW
 
+fan[1-*]_max	Fan maximum value
+		Unit: revolution/min (RPM)
+		Only rarely supported by the hardware.
+		RW
+
 fan[1-*]_input	Fan input value.
 		Unit: revolution/min (RPM)
 		RO
@@ -390,6 +395,7 @@ OR
 in[0-*]_min_alarm
 in[0-*]_max_alarm
 fan[1-*]_min_alarm
+fan[1-*]_max_alarm
 temp[1-*]_min_alarm
 temp[1-*]_max_alarm
 temp[1-*]_crit_alarm