usb: dwc3: fix extcon dependency

The dwc3 core support now links against the extcon subsystem,
so it cannot be built-in when extcon is a loadable module:

arm-linux-gnueabi-ld: drivers/usb/dwc3/core.o: in function `dwc3_get_extcon':
core.c:(.text+0x572): undefined reference to `extcon_get_edev_by_phandle'
arm-linux-gnueabi-ld: core.c:(.text+0x596): undefined reference to `extcon_get_extcon_dev'
arm-linux-gnueabi-ld: core.c:(.text+0x5ea): undefined reference to `extcon_find_edev_by_node'

There was already a Kconfig dependency in the dual-role support,
but this is now needed for the entire dwc3 driver.

It is still possible to build dwc3 without extcon, but this
prevents it from being set to built-in when extcon is a loadable
module.

Fixes: d182c2e ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present")
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Acked-by: Thinh Nguyen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: arndb

drivers/usb/dwc3/Kconfig

@@ -3,6 +3,7 @@
 config USB_DWC3
 	tristate "DesignWare USB3 DRD Core Support"
 	depends on (USB || USB_GADGET) && HAS_DMA
+	depends on (EXTCON || EXTCON=n)
 	select USB_XHCI_PLATFORM if USB_XHCI_HCD
 	select USB_ROLE_SWITCH if USB_DWC3_DUAL_ROLE
 	help
@@ -44,7 +45,6 @@ config USB_DWC3_GADGET
 config USB_DWC3_DUAL_ROLE
 	bool "Dual Role mode"
 	depends on ((USB=y || USB=USB_DWC3) && (USB_GADGET=y || USB_GADGET=USB_DWC3))
-	depends on (EXTCON=y || EXTCON=USB_DWC3)
 	help
 	  This is the default mode of working of DWC3 controller where
 	  both host and gadget features are enabled.