Added CAN API for STM32F1xx family.

* STM32F1xx family have only one CAN bus

Change-Id: Ie1c82a22e1483fc5d389b958d062f561770f9004

Author: BartSX

hal/targets/hal/TARGET_STM/TARGET_STM32F1/PeripheralPins.h

@@ -59,4 +59,9 @@ extern const PinMap PinMap_SPI_MISO[];
 extern const PinMap PinMap_SPI_SCLK[];
 extern const PinMap PinMap_SPI_SSEL[];
 
+//*** CAN ***
+
+extern const PinMap PinMap_CAN_RD[];
+extern const PinMap PinMap_CAN_TD[];
+
 #endif