RDMA/ucm: Allow user to specify QP type when creating id

Allow the user to indicate the QP type separately from the port space
when allocating an rdma_cm_id.  With RDMA_PS_IB, there is no longer a
1:1 relationship between the QP type and port space, so we need to
switch on the QP type to select between UD and connected QPs.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>