team: allow TSO being set on master

This patch allows TSO being set/unset on the master, so that GSO
segmentation is done after team layer.

Similar patch is present for bonding:
	b0ce3508 ("bonding: allow TSO being set on bonding master")
and bridge:
	f902e881 ("bridge: Add ability to enable TSO")

Suggested-by: Jiri Prochazka <jprochaz@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>