linux-phytec-fsl

cdc-ether: extract usbnet_cdc_update_filter function

This will be used by the set_rx_mode callback.

Also move a comment about multicast filtering in this new function.

Signed-off-by: Olivier Blin <olivier.blin@softathome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>