AC_WPNav: minor formatting fix

non-functional change

libraries/AC_WPNav/AC_WPNav.cpp

@@ -370,7 +370,7 @@ void AC_WPNav::update_brake(float ekfGndSpdLimit, float ekfNavVelGainScaler)
     if (dt >= _pos_control.get_dt_xy()) {
 
         // send adjusted feed forward velocity back to position controller
-        _pos_control.set_desired_velocity_xy(0,0);
+        _pos_control.set_desired_velocity_xy(0.0f, 0.0f);
         _pos_control.update_xy_controller(AC_PosControl::XY_MODE_POS_LIMITED_AND_VEL_FF, ekfNavVelGainScaler, false);
     }
 }