RC_Channel: remove UINT16_MAX check, moved to mavlink handler

libraries/RC_Channel/RC_Channel.cpp

@@ -332,12 +332,7 @@ void RC_Channel::set_override(const uint16_t v, const uint32_t timestamp_us)
     if (!rc().gcs_overrides_enabled()) {
         return;
     }
-    // this UINT16_MAX stuff should really, really be in the
-    // mavlink packet handling code.  It can be moved once that
-    // code is in the GCS_MAVLink class!
-    if (v == UINT16_MAX) {
-        return;
-    }
+
     last_override_time = timestamp_us != 0 ? timestamp_us : AP_HAL::millis();
     override_value = v;
     rc().new_override_received();