bsps/arm: Set VBAR in start.S

Set the VBAR to the vector table in the start section before
bsp_start_hook_0() is called to earlier handle exceptions in RTEMS.

Set the VBAR to the normal vector table in start.S for the main
processor.  Secondary processors set it in bsp_start_hook_0().

Update #4202.

bsps/arm/raspberrypi/start/bspstarthooks.c

@@ -117,9 +117,6 @@ void BSP_START_TEXT_SECTION bsp_start_hook_0(void)
   /* Clear Translation Table Base Control Register */
   arm_cp15_set_translation_table_base_control_register(0);
 
-  /* Clear Secure or Non-secure Vector Base Address Register */
-  arm_cp15_set_vector_base_address(bsp_vector_table_begin);
-
 #ifdef RTEMS_SMP
   if (cpu_index_self == 0) {
     rpi_ipi_initialize();