a. Common tree of `dir` structures.
b. Multi-port devices structures.

CC: Francious Romieu <romieu@fz.zoreil.com>
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>