LandingGear: remove unused enabled method

Also minor formatting fix

libraries/AP_LandingGear/AP_LandingGear.cpp

@@ -61,7 +61,7 @@ void AP_LandingGear::update()
     // if there is a force deploy active, disable retraction, then reset force deploy to consume it
     // gear will be deployed automatically because _retract_enabled is false.
     // this will disable retract switch until it is cycled through deploy position
-    if ( _force_deploy){
+    if (_force_deploy){
             enable(false);
             force_deploy(false);
         }

libraries/AP_LandingGear/AP_LandingGear.h

@@ -32,9 +32,6 @@ public:
         AP_Param::setup_object_defaults(this, var_info);
     }
 
-    /// enabled - returns true if landing gear retract is enabled
-    bool enabled() const { return _retract_enabled; }
-
     /// deployed - returns true if the landing gear is deployed
     bool deployed() const { return _deployed; }