ehci: clear suspend bit on detach

When a device is detached, clear the suspend bit (PORTSC_SUSPEND)
in the port status register.

The specs are not *that* clear what is supposed to happen in case
a suspended device is unplugged.  But the enable bit (PORTSC_PED)
is cleared, and the specs mention setting suspend with enable being
unset is undefined behavior.  So clearing them both looks reasonable,
and it actually fixes the reported bug.

https://bugzilla.redhat.com/show_bug.cgi?id=1268879

Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1445413462-18004-1-git-send-email-kraxel@redhat.com
