CVE-2021-47616 RDMA: Fix use-after-free in rxe_queue_cleanup

In the Linux kernel, the following vulnerability has been resolved:

RDMA: Fix use-after-free in rxe_queue_cleanup

On error handling path in rxe_qp_from_init() qp->sq.queue is freed and
then rxe_create_qp() will drop last reference to this object. qp clean up
function will try to free this queue one time and it causes UAF bug.

Fix it by zeroing queue pointer after freeing queue in rxe_qp_from_init().