Add support for registering existing interfaces

This adds support for native and slcan interfaces which are already
configured up to be registered in the CAN bus HAL.

Bug: 142655647
Test: manual
Change-Id: Ifd129db14dbf473bb627ebc9b9d13f5cb945b611
diff --git a/automotive/can/1.0/default/CanBusSlcan.h b/automotive/can/1.0/default/CanBusSlcan.h
index 3328a9f..2328a2c 100644
--- a/automotive/can/1.0/default/CanBusSlcan.h
+++ b/automotive/can/1.0/default/CanBusSlcan.h
@@ -32,6 +32,8 @@
     virtual bool postDown() override;
 
   private:
+    ICanController::Result updateIfaceName(base::unique_fd& uartFd);
+
     const std::string mUartName;
     const uint32_t kBitrate;
     base::unique_fd mFd;