exter memory axi err register
| EXTER_RID_ERR_CNT | AXI read id err cnt |
| EXTER_RRESP_ERR_CNT | AXI read resp err cnt |
| EXTER_WRESP_ERR_CNT | AXI write resp err cnt |
| EXTER_RD_FIFO_CNT | AXI read cmd fifo remain cmd count |
| EXTER_RD_BAK_FIFO_CNT | AXI read backup cmd fifo remain cmd count |
| EXTER_WR_FIFO_CNT | AXI write cmd fifo remain cmd count |
| EXTER_WR_BAK_FIFO_CNT | AXI write backup cmd fifo remain cmd count |