[PATCH 4.9 16/80] usb: gadget: legacy gadgets are optional

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Romain Izard <romain.izard.pro@xxxxxxxxx>

commit 6e253d0fbc665b36192b8ed3cecdbb65b413a1eb upstream.

With commit bc49d1d17dcf ("usb: gadget: don't couple configfs to legacy
gadgets"),it is possible to build a modular kernel with both built-in
configfs support and modular legacy gadget drivers.

But when building a kernel without modules, it is also necessary to be
able to build with configfs but without any legacy gadget driver. This
was a possible configuration when the USB_CONFIGFS was a part of the
choice options, but not anymore.

Mark the choice for legacy gadget drivers as optional restores this.

Fixes: bc49d1d17dcf ("usb: gadget: don't couple configfs to legacy gadgets")
Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/gadget/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -460,6 +460,7 @@ config USB_CONFIGFS_F_TCM
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH
+	optional
 	help
 	  A Linux "Gadget Driver" talks to the USB Peripheral Controller
 	  driver through the abstract "gadget" API.  Some other operating