Bug fix only first focuser is visible

Due to the underlying device name setting, the fact that FocusLynx
has two independent drivers, its name setting does not work. With
this fix the device names of the two focusers are fix to FocusLynx F1/F2.

drivers/focuser/focuslynx.cpp

@@ -48,6 +48,8 @@ FocusLynxF1::FocusLynxF1(const char *target)
      * F1 or F2 to set the target of the created instance
      */
     setFocusTarget(target);
+    // set the focuser name to a fixed value to ensure that both focusers are visible
+    setDeviceName(FocusLynxF1::getDefaultName());
 
     // Both communication available, Serial and network (tcp/ip)
     setSupportedConnections(CONNECTION_SERIAL | CONNECTION_TCP);
@@ -752,6 +754,8 @@ void FocusLynxF1::setDebug(bool enable)
 FocusLynxF2::FocusLynxF2(const char *target)
 {
     setFocusTarget(target);
+    // set the focuser name to a fixed value to ensure that both focusers are visible
+    setDeviceName(FocusLynxF2::getDefaultName());
 
     // The second focuser has no direct communication with the hub
     setSupportedConnections(CONNECTION_NONE);