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 <rdunlap@xenotime.net>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>