AP_HAL_Empty: Add support for using SPI devices of the same type.

libraries/AP_HAL_Empty/SPIDriver.cpp

@@ -41,7 +41,7 @@ EmptySPIDeviceManager::EmptySPIDeviceManager()
 void EmptySPIDeviceManager::init(void *)
 {}
 
-AP_HAL::SPIDeviceDriver* EmptySPIDeviceManager::device(enum AP_HAL::SPIDevice)
+AP_HAL::SPIDeviceDriver* EmptySPIDeviceManager::device(enum AP_HAL::SPIDevice, uint8_t index)
 {
     return &_device;
 }

libraries/AP_HAL_Empty/SPIDriver.h

@@ -24,7 +24,7 @@ class Empty::EmptySPIDeviceManager : public AP_HAL::SPIDeviceManager {
 public:
     EmptySPIDeviceManager();
     void init(void *);
-    AP_HAL::SPIDeviceDriver* device(enum AP_HAL::SPIDevice);
+    AP_HAL::SPIDeviceDriver* device(enum AP_HAL::SPIDevice, uint8_t index);
 private:
     EmptySPIDeviceDriver _device;
 };