Fix mqqtTopic global

I guess I missed a push on git.. so back port this missing stuff.

config.go

@@ -10,7 +10,6 @@ import (
 )
 
 var (
-	mqttTopic     = "zigbee2mqtt"
 	mqttClientID  = "z2m-" + uuid.New().String()
 	ignoredTopics = []string{
 		"bridge/groups",

gateway.go

@@ -34,8 +34,8 @@ func (gw *Gateway) AddZDevice(zDev *Z2MDevice) {
 		slog.Debug("Adding device", "dev", dev.String())
 		gw.Engine.AddDevice(dev)
 	}
-	gw.Devices[zDev.FriendlyName] = zDev
 	zDev.Gateway = gw
+	gw.Devices[zDev.FriendlyName] = zDev
 }
 
 func (gw *Gateway) RemoveZDevice(zDev *Z2MDevice) {

z2m.go

@@ -61,7 +61,7 @@ type Feature struct {
 
 // returns the topic for the device
 func (zDev *Z2MDevice) getTopic() string {
-	return mqttTopic + "/" + zDev.FriendlyName
+	return zDev.Gateway.Config.topic + "/" + zDev.FriendlyName
 }
 
 // return the expose with the given name
@@ -90,6 +90,8 @@ func (zDev *Z2MDevice) HandleMessage(msg mqtt.Message) {
 
 // creates new xAAL devices from a bridge device
 func (zDev *Z2MDevice) FindXAALDevices(gw *Gateway) {
+	// There is a trick here. We call FindXAALDevices w/ gw argument, but the Gateway is only set
+	// in the AddZDevice method. This is not mandatory but avoid to have Gateway at random place
 	baseAddr := gw.Config.baseAddr
 	ieeeAddr, _ := hexStringToInteger(zDev.IeeeAddress)
 	baseAddr, _ = baseAddr.Add(int64(ieeeAddr))