fix build of EHCI debug port code when USB_CHIPIDEA but !USB_EHCI_HCD

Relax condition of building the reset interface stubs in
drivers/usb/early/ehci-dbgp.c from USB_EHCI_HCD to just USB, to also
cover the chipidea driver re-using code from ehci-hcd.

Reported-by: Randy Dunlap <[e-mail]>
Signed-off-by: Jan Beulich <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Cc: Konrad Rzeszutek Wilk <[e-mail]>
Cc: Stefano Stabellini <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/early/ehci-dbgp.c

···
 	.index =	-1,
 };
 
-#if IS_ENABLED(CONFIG_USB_EHCI_HCD)
+#if IS_ENABLED(CONFIG_USB)
 int dbgp_reset_prep(struct usb_hcd *hcd)
 {
 	int ret = xen_dbgp_reset_prep(hcd);
···
 	return xen_dbgp_external_startup(hcd) ?: _dbgp_external_startup();
 }
 EXPORT_SYMBOL_GPL(dbgp_external_startup);
-#endif /* USB_EHCI_HCD */
+#endif /* USB */
 
 #ifdef CONFIG_KGDB