The USB_CDC_SET_ETHERNET_PACKET_FILTER request is mandatory for
CDC-ECM devices.  Accept this request, ignoring the actual filter
value (to match the existing behaviour for RNDIS).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
Message-Id: <20220906183053.3625472-3-mcb30@ipxe.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>