Fix bug with loopback implementation on LPC11c14. Changed 'CANCNTL_LBACK' to 'CANTEST_LBACK' like it is implemented in the C_CAN controller for the LPC1549.

Author: DC37

Diff for: libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/TARGET_LPC11CXX/can_api.c

@@ -71,7 +71,7 @@ int can_mode(can_t *obj, CanMode mode) {
             break;
         case MODE_TEST_SILENT:
             LPC_CAN->CNTL |= CANCNTL_TEST;
-            LPC_CAN->TEST |= (CANCNTL_LBACK | CANTEST_SILENT);
+            LPC_CAN->TEST |= (CANTEST_LBACK | CANTEST_SILENT);
             success = 1;
             break;
         case MODE_TEST_GLOBAL: