iio: ABI: generalize shunt_resistor attribute

Move ABI documentation for custom shunt resistor attributes into the
generic iio documentation file. Exception for pac1934: leave it
untouched since it does not comply with common iio ABI generalization.
Signed-off-by: Matteo Martelli <matteomartelli3@gmail.com>
Link: https://patch.msgid.link/20240722-iio-pac1921-v3-2-05dc9916cb33@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -2290,3 +2290,11 @@ KernelVersion:	6.7
 Contact:	linux-iio@vger.kernel.org
 Description:
 		List of available timeout value for tap gesture confirmation.
+
+What:		/sys/.../iio:deviceX/in_shunt_resistor
+What:		/sys/.../iio:deviceX/in_current_shunt_resistor
+What:		/sys/.../iio:deviceX/in_power_shunt_resistor
+KernelVersion:	6.10
+Contact:	linux-iio@vger.kernel.org
+Description:
+		The value of current sense resistor in Ohms.

Documentation/ABI/testing/sysfs-bus-iio-adc-max9611

-What:		/sys/bus/iio/devices/iio:deviceX/in_power_shunt_resistor
-Date:		March 2017
-KernelVersion:	4.12
-Contact:	linux-iio@vger.kernel.org
-Description: 	The value of the shunt resistor used to compute power drain on
-                common input voltage pin (RS+). In Ohms.
-
-What:		/sys/bus/iio/devices/iio:deviceX/in_current_shunt_resistor
-Date:		March 2017
-KernelVersion:	4.12
-Contact:	linux-iio@vger.kernel.org
-Description: 	The value of the shunt resistor used to compute current flowing
-                between RS+ and RS- voltage sense inputs. In Ohms.
-
-These attributes describe a single physical component, exposed as two distinct
-attributes as it is used to calculate two different values: power load and
-current flowing between RS+ and RS- inputs.

Documentation/ABI/testing/sysfs-bus-iio-ina2xx-adc

@@ -13,12 +13,3 @@ Description:
 		available for reading data. However, samples can be occasionally skipped
 		or repeated, depending on the beat between the capture and conversion
 		rates.
-
-What:		/sys/bus/iio/devices/iio:deviceX/in_shunt_resistor
-Date:		December 2015
-KernelVersion:	4.4
-Contact:	linux-iio@vger.kernel.org
-Description:
-		The value of the shunt resistor may be known only at runtime fom an
-		eeprom content read by a client application. This attribute allows to
-		set its value in ohms.