Clear fault status before halting

Now that halt functions allow re-directing execution to an unprivileged
handler, we need to make sure that the bus fault status is cleared
before halting, otherwise two consecutive faults would have a spurious
state.

Fixes: ba18966 Move fault status register clearing to end of handler

Author: AlessandroA

core/system/src/mpu/vmpu_armv7m.c

@@ -230,6 +230,7 @@ void vmpu_sys_mux_handler(uint32_t lr, uint32_t msp)
 
                 /* if recovery was not successful, throw an error and halt */
                 DEBUG_FAULT(FAULT_MEMMANAGE, lr, psp);
+                VMPU_SCB_MMFSR = fault_status;
                 HALT_ERROR(PERMISSION_DENIED, "Access to restricted resource denied");
             }
             else

core/system/src/mpu/vmpu_freescale_k64.c

@@ -90,6 +90,7 @@ void vmpu_sys_mux_handler(uint32_t lr, uint32_t msp)
 
                 /* if recovery was not successful, throw an error and halt */
                 DEBUG_FAULT(FAULT_BUS, lr, psp);
+                VMPU_SCB_BFSR = fault_status;
                 HALT_ERROR(PERMISSION_DENIED, "Access to restricted resource denied");
             }
             else