AP_UAVCAN: allow CAN output for function==0 and allow for 32 CAN servos

libraries/AP_UAVCAN/AP_UAVCAN.cpp

@@ -580,7 +580,7 @@ void AP_UAVCAN::SRV_push_servos()
 
     for (uint8_t i = 0; i < UAVCAN_SRV_NUMBER; i++) {
         // Check if this channels has any function assigned
-        if (SRV_Channels::channel_function(i) > SRV_Channel::k_none) {
+        if (SRV_Channels::channel_function(i) >= SRV_Channel::k_none) {
             _SRV_conf[i].pulse = SRV_Channels::srv_channel(i)->get_output_pwm();
             _SRV_conf[i].esc_pending = true;
             _SRV_conf[i].servo_pending = true;

libraries/AP_UAVCAN/AP_UAVCAN.h

@@ -31,11 +31,11 @@
 #include <uavcan/protocol/param/GetSet.hpp>
 #include <uavcan/protocol/param/ExecuteOpcode.hpp>
 #include <uavcan/helpers/heap_based_pool_allocator.hpp>
-
+#include <SRV_Channel/SRV_Channel.h>
 
 
 #ifndef UAVCAN_SRV_NUMBER
-#define UAVCAN_SRV_NUMBER 18
+#define UAVCAN_SRV_NUMBER NUM_SERVO_CHANNELS
 #endif
 
 #define AP_UAVCAN_SW_VERS_MAJOR 1