AP_BoardConfig_CAN: const some accessors

libraries/AP_BoardConfig/AP_BoardConfig_CAN.h

@@ -32,10 +32,10 @@ public:
     void init(void);
 
     // returns number of active CAN drivers
-    uint8_t get_num_drivers(void) { return _num_drivers; }
+    uint8_t get_num_drivers(void) const { return _num_drivers; }
 
     // return debug level for interface i
-    uint8_t get_debug_level(uint8_t i) {
+    uint8_t get_debug_level(uint8_t i) const {
 #if AP_CAN_DEBUG
         if (i < MAX_NUMBER_OF_CAN_INTERFACES) {
             return _interfaces[i]._driver_number_cache ? _interfaces[i]._debug_level : 0;
@@ -45,7 +45,7 @@ public:
     }
 
     // return maximum level of debug of all interfaces
-    uint8_t get_debug_level(void) {
+    uint8_t get_debug_level(void) const {
         uint8_t ret = 0;
 #if AP_CAN_DEBUG
         for (uint8_t i = 0; i < MAX_NUMBER_OF_CAN_INTERFACES; i++) {
@@ -57,7 +57,7 @@ public:
     }
 
     // return maximum level of debug for driver index i
-    uint8_t get_debug_level_driver(uint8_t i) {
+    uint8_t get_debug_level_driver(uint8_t i) const {
         uint8_t ret = 0;
 #if AP_CAN_DEBUG
         for (uint8_t j = 0; j < MAX_NUMBER_OF_CAN_INTERFACES; j++) {
@@ -71,7 +71,7 @@ public:
     }
 
     // return driver for index i
-    AP_HAL::CANProtocol* get_driver(uint8_t i) {
+    AP_HAL::CANProtocol* get_driver(uint8_t i) const {
         if (i < MAX_NUMBER_OF_CAN_DRIVERS) {
             return _drivers[i]._driver;
         }
@@ -79,7 +79,7 @@ public:
     }
 
     // return protocol type index i
-    Protocol_Type get_protocol_type(uint8_t i) {
+    Protocol_Type get_protocol_type(uint8_t i) const {
         if (i < MAX_NUMBER_OF_CAN_DRIVERS) {
             return _drivers[i]._protocol_type_cache;
         }