doc/configuration: move driver details from ModbusRTU resource to ModbusRTUDriver

Signed-off-by: Bastian Krause <bst@pengutronix.de>

Author: Bastian-Krause

doc/configuration.rst

@@ -79,14 +79,7 @@ Modbus is normally implemented on top of RS-485, though this is not strictly
 necessary, as long as the Modbus network only has one master (and up to 256
 slaves).
 
-The labgrid driver is implemented using the
-`minimalmodbus <https://minimalmodbus.readthedocs.io/en/stable/>`_ Python
-library.
-The implementation only supports that labgrid will be the master on the Modbus
-network.
-
-This resource and driver only supports local usage and will not work with an
-exporter.
+This resource only supports local usage and will not work with an exporter.
 
 .. code-block:: yaml
 
@@ -1556,6 +1549,12 @@ ModbusRTUDriver
 A :any:`ModbusRTUDriver` connects to a ModbusRTU resource. This driver only
 supports local usage and will not work with an exporter.
 
+The driver is implemented using the
+`minimalmodbus <https://minimalmodbus.readthedocs.io/en/stable/>`_ Python
+library.
+The implementation only supports that labgrid will be the master on the Modbus
+network.
+
 .. code-block:: yaml
 
     ModbusRTUDriver: {}