scsi: hisi_sas: Block requests before take debugfs snapshot

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7BNF8


CVE: NA

----------------------------------------------------------------------

When the FIO is running and the dump is triggered continuously, some SATA
I/Os fail to be returned to the upper layer due to the setting of
HISI_SAS_REJECT_CMD_BIT. The SCSI layer invokes the error processing
thread. However, sas_ata_hard_reset() also fails to be reset due to the
setting of HISI_SAS_REJECT_CMD_BIT. As a result, the device is disabled.
Call scsi_block_requests() and wait command complete before setting
HISI_SAS_REJECT_CMD_BIT to avoid SATA I/O failures.

Signed-off-by: Yihang Li <liyihang9@huawei.com>
Signed-off-by: xiabing <xiabing12@h-partners.com>