usb-ehci: always call ehci_queues_rip_unused for period queues

Before this patch USB 2 devices with interrupt endpoints were not working
properly. The problem is that to avoid loops we stop processing as soon
as we encounter a queue-head (qh) we've already seen since qhs can be linked
in a circular fashion, this is tracked by the seen flag in our qh struct.

The resetting of the seen flag is done from ehci_queues_rip_unused which
before this patch was only called when executing the statemachine for the
async schedule.

But packets for interrupt endpoints are part of the periodic schedule! So what
would happen is that when there were no ctrl or bulk packets for a USB 2
device with an interrupt endpoint, the async schedule would become non
active, then ehci_queues_rip_unused would no longer get called and when
processing the qhs for the interrupt endpoints from the periodic schedule
their seen bit would still be 1 and they would be skipped.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
