usb: Clear host_endpoint->streams when implicitly freeing streams

If streams are still allocated on device-reset or set-interface then the hcd
code implictly frees the streams. Clear host_endpoint->streams in this case
so that if a driver later tries to re-allocate them it won't run afoul of the
device already having streams check in usb_alloc_streams().

Note normally streams still being allocated at reset / set-intf  would be a
driver bug, but this can happen without it being a driver bug on reset-resume.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>