[DISC] Removal of openHAB specific MQTT discovery patch (#2153)

Removal of openHAB specific MQTT discovery patch "ohdisc", as it is no longer required with openHAB 4.3 and later, and with openHAB before 4.3 MQTT discovery never was fully implemented anyway.

main/config_mqttDiscovery.h

@@ -140,11 +140,6 @@ char discovery_prefix[parameters_size + 1] = discovery_Prefix;
 #endif
 
 /*-------------- Auto discovery macros-----------------*/
-// Set the line below to true so as to have autodiscovery working with OpenHAB
-#ifndef OpenHABDiscovery
-#  define OpenHABDiscovery false
-#endif
-
 // Home assistant autodiscovery value key definition
 #define jsonBatt        "{{ value_json.batt | is_defined }}"
 #define jsonLux         "{{ value_json.lux | is_defined }}"