stmhal/can: clear FIFO flags in IRQ handler

HAL Driver before v1.4.2 had a bug which caused clearing all pending
flags in MSR, TSR, RF0R and RF1R instead of only the requested one.

This is why micropython got away without explicitly clearing flags
in IRQ handler.

stmhal/can.c

@@ -752,6 +752,8 @@ STATIC mp_obj_t pyb_can_rxcallback(mp_obj_t self_in, mp_obj_t fifo_in, mp_obj_t
         __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
         __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FF0 : CAN_IT_FF1);
         __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
+        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FF0 : CAN_FLAG_FF1);
+        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FOV0 : CAN_FLAG_FOV1);
         *callback = mp_const_none;
     } else if (*callback != mp_const_none) {
         // Rx call backs has already been initialized
@@ -847,11 +849,13 @@ void can_rx_irq_handler(uint can_id, uint fifo_id) {
             break;
         case RX_STATE_MESSAGE_PENDING:
             __HAL_CAN_DISABLE_IT(&self->can, (fifo_id == CAN_FIFO0) ? CAN_IT_FF0 : CAN_IT_FF1);
+            __HAL_CAN_CLEAR_FLAG(&self->can, (fifo_id == CAN_FIFO0) ? CAN_FLAG_FF0 : CAN_FLAG_FF1);
             irq_reason = MP_OBJ_NEW_SMALL_INT(1);
             *state = RX_STATE_FIFO_FULL;
             break;
         case RX_STATE_FIFO_FULL:
             __HAL_CAN_DISABLE_IT(&self->can, (fifo_id == CAN_FIFO0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
+            __HAL_CAN_CLEAR_FLAG(&self->can, (fifo_id == CAN_FIFO0) ? CAN_FLAG_FOV0 : CAN_FLAG_FOV1);
             irq_reason = MP_OBJ_NEW_SMALL_INT(2);
             *state = RX_STATE_FIFO_OVERFLOW;
             break;