Bluetooth: fix debugfs registration

Since commit ec6cef9 ("Bluetooth: Fix SMP channel registration for
unconfigured controllers") the debugfs interface for unconfigured
controllers will be created when the controller is configured.

There is however currently nothing preventing a controller from being
configured multiple time (e.g. setting the device address using btmgmt)
which results in failed attempts to register the already registered
debugfs entries:

	debugfs: File 'features' in directory 'hci0' already present!
	debugfs: File 'manufacturer' in directory 'hci0' already present!
	debugfs: File 'hci_version' in directory 'hci0' already present!
	...
	debugfs: File 'quirk_simultaneous_discovery' in directory 'hci0' already present!

Add a controller flag to avoid trying to register the debugfs interface
more than once.

Fixes: ec6cef9 ("Bluetooth: Fix SMP channel registration for unconfigured controllers")
Cc: stable@vger.kernel.org      # 4.0
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

include/net/bluetooth/hci.h

@@ -350,6 +350,7 @@ enum {
 enum {
 	HCI_SETUP,
 	HCI_CONFIG,
+	HCI_DEBUGFS_CREATED,
 	HCI_AUTO_OFF,
 	HCI_RFKILLED,
 	HCI_MGMT,

net/bluetooth/hci_sync.c

@@ -4551,6 +4551,9 @@ static int hci_init_sync(struct hci_dev *hdev)
 	    !hci_dev_test_flag(hdev, HCI_CONFIG))
 		return 0;
 
+	if (hci_dev_test_and_set_flag(hdev, HCI_DEBUGFS_CREATED))
+		return 0;
+
 	hci_debugfs_create_common(hdev);
 
 	if (lmp_bredr_capable(hdev))