Update reference to phoenixcontact_fl_2300 in configuration.rst

Author: SeminSey

doc/configuration.rst

@@ -195,7 +195,7 @@ Currently available are:
 ``netio_kshell``
   Controls a NETIO 4C PDU via a Telnet interface.
 
-``phoenix_fl_switch``
+``phoenixcontact_fl_2300``
   Controls a single-pair-ethernet powerswitch via telnet.
   Tested on a FL SWITCH 2303-8SP1 with FW-version 3.27.01 BETA