IB/ehca: Remove reference to special QP in case of port activation failure

If the initialization of a special QP (e.g. AQP1) fails due to a
software timeout, we have to remove the reference to that special QP
struct from the port struct to stop the driver from accessing the QP,
since it will be/has been destroyed by the caller, eg in this case
ib_mad.

Signed-off-by: Stefan Roscher <stefan.roscher@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>