AP_UAVCAN: disable CAN filtering except on AP_Periph

this saves flash space and makes CAN forwarding for any bus without
reconfigure/reboot easy. CAN filtering is not useful in the main
flight controller firmware as we want to see nearly all packets

libraries/AP_UAVCAN/AP_UAVCAN.cpp

@@ -357,9 +357,6 @@ void AP_UAVCAN::init(uint8_t driver_index, bool enable_filters)
     }
     
     _led_conf.devices_count = 0;
-    if (enable_filters) {
-        configureCanAcceptanceFilters(*_node);
-    }
 
     /*
      * Informing other nodes that we're ready to work.

libraries/AP_UAVCAN/AP_UAVCAN_IfaceMgr.cpp

@@ -93,27 +93,6 @@ int16_t CanIface::receive(CanFrame& out_frame, MonotonicTime& out_ts_monotonic,
     return ret;
 }
 
-/**
- * Configure the hardware CAN filters. @ref CanFilterConfig.
- *
- * @return 0 = success, negative for error.
- */
-int16_t CanIface::configureFilters(const CanFilterConfig* filter_configs, uint16_t num_configs)
-{
-    if (can_iface_ == UAVCAN_NULLPTR) {
-        return -1;
-    }
-    AP_HAL::CANIface::CanFilterConfig* hal_filter_configs = new AP_HAL::CANIface::CanFilterConfig[num_configs];
-    if (hal_filter_configs == nullptr) {
-        return -1;
-    }
-    for (uint16_t i = 0; i < num_configs; i++) {
-        hal_filter_configs[i].id = filter_configs[i].id;
-        hal_filter_configs[i].mask = filter_configs[i].mask;
-    }
-    return can_iface_->configureFilters(hal_filter_configs, num_configs);
-}
-
 /**
  * Number of available hardware filters.
  */

libraries/AP_UAVCAN/AP_UAVCAN_IfaceMgr.h

@@ -39,9 +39,11 @@ public:
     virtual int16_t receive(CanFrame& out_frame, MonotonicTime& out_ts_monotonic,
                             UtcTime& out_ts_utc, CanIOFlags& out_flags) override;
 
-    int16_t configureFilters(const CanFilterConfig* filter_configs,
-                             uint16_t num_configs) override;
-
+    virtual int16_t configureFilters(const CanFilterConfig* filter_configs,
+                                     uint16_t num_configs) override {
+        return 0;
+    }
+    
     uint16_t getNumFilters() const override;
 
     uint64_t getErrorCount() const override;