AP_WheelEncder: remove dead code

libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp

@@ -67,12 +67,6 @@ void AP_WheelEncoder_Quadrature::update(void)
     update_pin(last_pin_a, get_pin_a(), last_pin_a_value);
     update_pin(last_pin_b, get_pin_b(), last_pin_b_value);
 
-    static uint32_t last_warn_ms = 0;
-    const uint32_t now = AP_HAL::millis();
-    if (now - last_warn_ms > 1000) {
-        last_warn_ms = now;
-    }
-
     // disable interrupts to prevent race with irq_handler
     void *irqstate = hal.scheduler->disable_interrupts_save();