scsi: hisi_sas: process error codes according to their priority

There are some rules to decide which error code has the high priority
when errors happen together:

(1) Error phase of CQ decides the error happens on RX or TX;

(2) For TX error, when DMA/TRANS TX error happen simultaneously, the
    priority of DMA TX error is higher than TRANS TX error, so for the
    priority of TX error: DW2 (DMA TX part) > DW0;

(3) For RX error, when TRANS/DMA/SIPC RX error happen simultaneously,
    the priority of TRANS RX error is higher than DMA and SIPC RX error,
    and we should also keep the rules (the priority of DW3 > DW2), so
    for the priority of RX error: DW1 > DW3 > DW2(SIPC RX part);

(4) There are also a priority we should keep in the same error type.

So, modify slot error code to handle this.

In addition to this, some some error codes are modified according to
recommendation from SoC designer.
Signed-off-by: NXiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>