scsi: hisi_sas: Make three functions static

Fix sparse warnings:

drivers/scsi/hisi_sas/hisi_sas_main.c:3686:6:
 warning: symbol 'hisi_sas_debugfs_release' was not declared. Should it be static?
drivers/scsi/hisi_sas/hisi_sas_main.c:3708:5:
 warning: symbol 'hisi_sas_debugfs_alloc' was not declared. Should it be static?
drivers/scsi/hisi_sas/hisi_sas_main.c:3799:6:
 warning: symbol 'hisi_sas_debugfs_bist_init' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20190923054035.19036-1-yuehaibing@huawei.comReported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -3683,7 +3683,7 @@ void hisi_sas_debugfs_work_handler(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(hisi_sas_debugfs_work_handler);
 
-void hisi_sas_debugfs_release(struct hisi_hba *hisi_hba)
+static void hisi_sas_debugfs_release(struct hisi_hba *hisi_hba)
 {
 	struct device *dev = hisi_hba->dev;
 	int i;
@@ -3705,7 +3705,7 @@ void hisi_sas_debugfs_release(struct hisi_hba *hisi_hba)
 		devm_kfree(dev, hisi_hba->debugfs_port_reg[i]);
 }
 
-int hisi_sas_debugfs_alloc(struct hisi_hba *hisi_hba)
+static int hisi_sas_debugfs_alloc(struct hisi_hba *hisi_hba)
 {
 	const struct hisi_sas_hw *hw = hisi_hba->hw;
 	struct device *dev = hisi_hba->dev;
@@ -3796,7 +3796,7 @@ int hisi_sas_debugfs_alloc(struct hisi_hba *hisi_hba)
 	return -ENOMEM;
 }
 
-void hisi_sas_debugfs_bist_init(struct hisi_hba *hisi_hba)
+static void hisi_sas_debugfs_bist_init(struct hisi_hba *hisi_hba)
 {
 	hisi_hba->debugfs_bist_dentry =
 			debugfs_create_dir("bist", hisi_hba->debugfs_dir);