scsi: hisi_sas: unmask interrupts ent72 and ent74

The interrupts of ent72 and ent74 are not processed by PCIe AER handling,
so we need to unmask the interrupts and process them first in the driver.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>