Clock Driver Shell - ISR handler prototype should follow port interrupt model

The prototype for the clock driver tick isr varies based upon
the interrupt model used by the port. This driver was checking
solely upon a flag set by the BSP.

c/src/lib/libbsp/shared/clockdrv_shell.h

@@ -56,7 +56,8 @@ void Clock_exit( void );
  *
  *  Return values:      NONE
  */
-#ifdef BSP_FEATURE_IRQ_EXTENSION
+#if defined(BSP_FEATURE_IRQ_EXTENSION) || \
+    (CPU_SIMPLE_VECTORED_INTERRUPTS != TRUE)
 void Clock_isr(void *arg)
 {
 #else