fixed a mistake where I was adding "can not supprted" error at wrong place

aashishc1988 · aashishc1988 · commit a9ce00bb4dee · 2018-10-12T10:16:32.000-05:00
diff --git a/drivers/CAN.h b/drivers/CAN.h
@@ -304,8 +304,6 @@ class CAN : private NonCopyable<CAN> {
 
 } // namespace mbed
 
-#else
-    #error CAN NOT SUPPORTED
 #endif
 
 #endif    // MBED_CAN_H
