team: handle NETIF_F_HW_SWITCH_OFFLOAD flag and add ndo_bridge_setlink/dellink handlers

Currently ndo_bridge_setlink and ndo_bridge_dellink handlers point
to the default switchdev handlers

This follows my bonding driver changes.

I have only compile tested this patch. However similar
bonding code has been tested.

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