RDMA/restrack: Support all QP types

The latest changes in restrack name handling allowed to simplify the QP
creation code to support all types of QPs.

For example XRC QP are presented with rdmatool.

$ ibv_xsrq_pingpong &
$ rdma res show qp
link ibp0s9/1 lqpn 0 type SMI state RTS sq-psn 0 comm [ib_core]
link ibp0s9/1 lqpn 1 type GSI state RTS sq-psn 0 comm [ib_core]
link ibp0s9/1 lqpn 7 type UD state RTS sq-psn 0 comm [mlx5_ib]
link ibp0s9/1 lqpn 42 type XRC_TGT state INIT sq-psn 0 path-mig-state MIGRATED comm [ib_uverbs]
link ibp0s9/1 lqpn 43 type XRC_INI state INIT sq-psn 0 path-mig-state MIGRATED pdn 197 pid 419 comm ibv_xsrq_pingpong

Link: https://lore.kernel.org/r/20201117070148.1974114-4-leon@kernel.org
Reviewed-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>