HAL_PX4: implement device IDs for I2C and SPI

libraries/AP_HAL_PX4/I2CDevice.cpp

@@ -85,6 +85,8 @@ I2CDevice::I2CDevice(uint8_t bus, uint8_t address) :
     _px4dev(_busnum),
     _address(address)
 {
+    set_device_bus(_px4dev.map_bus_number(bus));
+    set_device_address(address);
 }
     
 I2CDevice::~I2CDevice()

libraries/AP_HAL_PX4/I2CWrapper.h

@@ -19,9 +19,10 @@ public:
     void set_retries(uint8_t retries) {
         _retries = retries;
     }
+
+    uint8_t map_bus_number(uint8_t bus) const;
     
 private:
-    uint8_t map_bus_number(uint8_t bus) const;
     static uint8_t instance;
     bool init_done;
     bool init_ok;

libraries/AP_HAL_PX4/SPIDevice.cpp

@@ -64,6 +64,8 @@ SPIDevice::SPIDevice(SPIBus &_bus, SPIDesc &_device_desc)
     : bus(_bus)
     , device_desc(_device_desc)
 {
+    set_device_bus(_bus.bus);
+    set_device_address(_device_desc.device);
 }
 
 SPIDevice::~SPIDevice()