bonding: handle NETIF_F_HW_SWITCH_OFFLOAD flag and add ndo_bridge_setlink/dellink handlers

We want bond to pick up the offload flag if any of its slaves have it.

NETIF_F_HW_SWITCH_OFFLOAD flag is added to the mask, so that
netdev_increment_features does not ignore it.

This also adds ndo_bridge_setlink and ndo_bridge_dellink handlers.
These currently point to the default handlers provided by the
switchdev api.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>