bnx2x: Add teardown_q and close to VF <-> PF channel

When a VF is being closed its queues are released via
the 'teardown_q' and the VF itself is closed with
'close'. These are essentially the unload counterparts of
'init' and 'setup_q' from the load flow.

Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>