team: use netdev_features_t instead of u32

This code was introduced in 2011 around the same time that we made
netdev_features_t a u64 type.  These days a u32 is not big enough to
hold all the potential features.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>