scsi: isci: Make isci_host_attrs static

This eliminates the following sparse warning:

drivers/scsi/isci/init.c:145:25: warning: symbol 'isci_host_attrs' was
not declared. Should it be static?

Link: https://lore.kernel.org/r/20200912033741.142415-1-yanaijie@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/isci/init.c

@@ -142,7 +142,7 @@ static ssize_t isci_show_id(struct device *dev, struct device_attribute *attr, c
 
 static DEVICE_ATTR(isci_id, S_IRUGO, isci_show_id, NULL);
 
-struct device_attribute *isci_host_attrs[] = {
+static struct device_attribute *isci_host_attrs[] = {
 	&dev_attr_isci_id,
 	NULL
 };