docs: hwmon: Add attributes to report rated values

New attributes (rated_min/rated_max) are being added the hwmon ABI.
They are needed to cover rated values documented by PMBus
specification:
PMBus Power System Mgt Protocol Specification - Part II – Revision 1.3.1,
chapters: 22.3.1 - 22.3.10, 22.3.15
Signed-off-by: Zbigniew Lukwinski <zbigniew.lukwinski@linux.intel.com>
Link: https://lore.kernel.org/r/1596224237-32280-2-git-send-email-zbigniew.lukwinski@linux.intel.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/sysfs-interface.rst

@@ -241,6 +241,20 @@ Voltages
 		Affects the way the driver calculates the CPU core reference
 		voltage from the vid pins.
 
+`in[0-*]_rated_min`
+		Minimum rated voltage.
+
+		Unit: millivolt
+
+		RO
+
+`in[0-*]_rated_max`
+		Maximum rated voltage.
+
+		Unit: millivolt
+
+		RO
+
 Also see the Alarms section for status flags associated with voltages.
 
 
@@ -574,6 +588,20 @@ Temperatures
 
 		RW
 
+`temp[1-*]_rated_min`
+		Minimum rated temperature.
+
+		Unit: millidegree Celsius
+
+		RO
+
+`temp[1-*]_rated_max`
+		Maximum rated temperature.
+
+		Unit: millidegree Celsius
+
+		RO
+
 Some chips measure temperature using external thermistors and an ADC, and
 report the temperature measurement as a voltage. Converting this voltage
 back to a temperature (or the other way around for limits) requires
@@ -664,6 +692,20 @@ Currents
 
 		RW
 
+`curr[1-*]_rated_min`
+		Minimum rated current.
+
+		Unit: milliampere
+
+		RO
+
+`curr[1-*]_rated_max`
+		Maximum rated current.
+
+		Unit: milliampere
+
+		RO
+
 Also see the Alarms section for status flags associated with currents.
 
 *****
@@ -830,6 +872,20 @@ Power
 
 				RW
 
+`power[1-*]_rated_min`
+				Minimum rated power.
+
+				Unit: microWatt
+
+				RO
+
+`power[1-*]_rated_max`
+				Maximum rated power.
+
+				Unit: microWatt
+
+				RO
+
 Also see the Alarms section for status flags associated with power readings.
 
 ******
@@ -877,6 +933,20 @@ Humidity
 
 				RW
 
+`humidity[1-*]_rated_min`
+				Minimum rated humidity.
+
+				Unit: milli-percent (per cent mille, pcm)
+
+				RO
+
+`humidity[1-*]_rated_max`
+				Maximum rated humidity.
+
+				Unit: milli-percent (per cent mille, pcm)
+
+				RO
+
 ******
 Alarms
 ******