Bluetooth: Remove debugfs directory on module init failure

If bt_init() fails, the debugfs directory currently is not removed. If
the module is loaded again after that, the debugfs directory is not set
up properly due to the existing directory.

# modprobe bluetooth
# ls -laF /sys/kernel/debug/bluetooth
total 0
drwxr-xr-x 2 root root 0 Sep 27 14:26 ./
drwx------ 31 root root 0 Sep 27 14:25 ../
-r--r--r-- 1 root root 0 Sep 27 14:26 l2cap
-r--r--r-- 1 root root 0 Sep 27 14:26 sco
# modprobe -r bluetooth
# ls -laF /sys/kernel/debug/bluetooth
ls: cannot access '/sys/kernel/debug/bluetooth': No such file or directory
#

# modprobe bluetooth
modprobe: ERROR: could not insert 'bluetooth': Invalid argument
# dmesg | tail -n 6
Bluetooth: Core ver 2.22
NET: Registered PF_BLUETOOTH protocol family
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: Faking l2cap_init() failure for testing
NET: Unregistered PF_BLUETOOTH protocol family
# ls -laF /sys/kernel/debug/bluetooth
total 0
drwxr-xr-x 2 root root 0 Sep 27 14:31 ./
drwx------ 31 root root 0 Sep 27 14:26 ../
#

# modprobe bluetooth
# dmesg | tail -n 7
Bluetooth: Core ver 2.22
debugfs: Directory 'bluetooth' with parent '/' already present!
NET: Registered PF_BLUETOOTH protocol family
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: L2CAP socket layer initialized
Bluetooth: SCO socket layer initialized
# ls -laF /sys/kernel/debug/bluetooth
total 0
drwxr-xr-x 2 root root 0 Sep 27 14:31 ./
drwx------ 31 root root 0 Sep 27 14:26 ../
#

Cc: [e-mail]
Fixes: ffcecac6a738 ("Bluetooth: Create root debugfs directory during module init")
Signed-off-by: Aaron Thompson <[e-mail]>
Signed-off-by: Luiz Augusto von Dentz <[e-mail]>

net/bluetooth/af_bluetooth.c

···
 	bt_sysfs_cleanup();
 cleanup_led:
 	bt_leds_cleanup();
+	debugfs_remove_recursive(bt_debugfs);
 	return err;
 }