switchdev: respect SKIP_EOPNOTSUPP flag in case there is no recursion

Caller passing down the SKIP_EOPNOTSUPP switchdev flag expects that
-EOPNOTSUPP cannot be returned. But in case of direct op call without
recurtion, this may happen. So fix this by checking it always on the
end of __switchdev_port_attr_set function.

Fixes: 464314ea ("switchdev: skip over ports returning -EOPNOTSUPP when recursing ports")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>