[Bluetooth] Add SCO support to btusb driver

The new generic driver for Bluetooth USB devices was missing proper
SCO support. The driver now claims the second interface for these USB
devices to allow the flow of SCO packets. It also handles switching
of the alternate setting and re-submission of isochronous URBs.

The btusb driver is now a full replacement for hci_usb and thus the
experimental tag has been removed and this driver is promoted as
preferred one.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/Kconfig

@@ -3,8 +3,8 @@ menu "Bluetooth device drivers"
 	depends on BT
 
 config BT_HCIUSB
-	tristate "HCI USB driver"
-	depends on USB
+	tristate "HCI USB driver (old version)"
+	depends on USB && BT_HCIBTUSB=n
 	help
 	  Bluetooth HCI USB driver.
 	  This driver is required if you want to use Bluetooth devices with
@@ -23,15 +23,13 @@ config BT_HCIUSB_SCO
 	  Say Y here to compile support for SCO over HCI USB.
 
 config BT_HCIBTUSB
-	tristate "HCI USB driver (alternate version)"
-	depends on USB && EXPERIMENTAL && BT_HCIUSB=n
+	tristate "HCI USB driver"
+	depends on USB
 	help
 	  Bluetooth HCI USB driver.
 	  This driver is required if you want to use Bluetooth devices with
 	  USB interface.
 
-          This driver is still experimental and has no SCO support.
-
 	  Say Y here to compile support for Bluetooth USB devices into the
 	  kernel or say M to compile it as module (btusb).