Bluetooth: hci_core: Fix build warnings

This fixes the following warnings:

net/bluetooth/hci_core.c: In function ‘hci_register_dev’:
net/bluetooth/hci_core.c:2620:54: warning: ‘%d’ directive output may
be truncated writing between 1 and 10 bytes into a region of size 5
[-Wformat-truncation=]
 2620 |         snprintf(hdev->name, sizeof(hdev->name), "hci%d", id);
      |                                                      ^~
net/bluetooth/hci_core.c:2620:50: note: directive argument in the range
[0, 2147483647]
 2620 |         snprintf(hdev->name, sizeof(hdev->name), "hci%d", id);
      |                                                  ^~~~~~~
net/bluetooth/hci_core.c:2620:9: note: ‘snprintf’ output between 5 and
14 bytes into a destination of size 8
 2620 |         snprintf(hdev->name, sizeof(hdev->name), "hci%d", id);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

include/net/bluetooth/hci_core.h

@@ -350,7 +350,7 @@ struct hci_dev {
 	struct list_head list;
 	struct mutex	lock;
 
-	char		name[8];
+	const char	*name;
 	unsigned long	flags;
 	__u16		id;
 	__u8		bus;

net/bluetooth/hci_core.c

@@ -2617,7 +2617,11 @@ int hci_register_dev(struct hci_dev *hdev)
 	if (id < 0)
 		return id;
 
-	snprintf(hdev->name, sizeof(hdev->name), "hci%d", id);
+	error = dev_set_name(&hdev->dev, "hci%u", id);
+	if (error)
+		return error;
+
+	hdev->name = dev_name(&hdev->dev);
 	hdev->id = id;
 
 	BT_DBG("%p name %s bus %d", hdev, hdev->name, hdev->bus);
@@ -2639,8 +2643,6 @@ int hci_register_dev(struct hci_dev *hdev)
 	if (!IS_ERR_OR_NULL(bt_debugfs))
 		hdev->debugfs = debugfs_create_dir(hdev->name, bt_debugfs);
 
-	dev_set_name(&hdev->dev, "%s", hdev->name);
-
 	error = device_add(&hdev->dev);
 	if (error < 0)
 		goto err_wqueue;