net/smc: use device link provided in qp_context

The device field of the IB event structure does not always point to the
SMC IB device. Load the pointer from the qp_context which is always
provided to smc_ib_qp_event_handler() in the priv field. And for qp
events the affected port is given in the qp structure of the ibevent,
derive it from there.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>