scsi: hisi_sas: Delete some unused callbacks

The debugfs code has been relocated to v3 hw driver, so delete unused
struct hisi_sas_hw function pointers snapshot_{prepare, restore}.

Link: https://lore.kernel.org/r/1617709711-195853-2-git-send-email-john.garry@huawei.comSigned-off-by: NLuo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -346,8 +346,6 @@ struct hisi_sas_hw {
 				u8 reg_index, u8 reg_count, u8 *write_data);
 	void (*wait_cmds_complete_timeout)(struct hisi_hba *hisi_hba,
 					   int delay_ms, int timeout_ms);
-	void (*snapshot_prepare)(struct hisi_hba *hisi_hba);
-	void (*snapshot_restore)(struct hisi_hba *hisi_hba);
 	int complete_hdr_size;
 	struct scsi_host_template *sht;
 };