hisi_sas: add hisi_sas_slot_abort()

Add a function to abort a slot (task) in the target
device and then cleanup and complete the task.
The function is called from work queue context as
it cannot be called from the context where it is
triggered (interrupt).
Flag hisi_sas_slot.abort is added as the flag used
in the slot error handler to indicate whether the
slot needs to be aborted in the sdev prior to
cleanup and finish.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 02da7e4..c92e65b 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -112,6 +112,7 @@
 	int	cmplt_queue;
 	int	cmplt_queue_slot;
 	int	idx;
+	int	abort;
 	void	*cmd_hdr;
 	dma_addr_t cmd_hdr_dma;
 	void	*status_buffer;
@@ -120,6 +121,7 @@
 	dma_addr_t command_table_dma;
 	struct hisi_sas_sge_page *sge_page;
 	dma_addr_t sge_page_dma;
+	struct work_struct abort_slot;
 };
 
 struct hisi_sas_tmf_task {