rdma/qedr: Fix crash due to redundant release of device's qp memory

Device's QP memory should only be allocated and released by IB layer.
This patch removes the redundant release of the device's qp memory and
uses completion APIs to make sure that .destroy_qp() only return, when qp
reference becomes 0.

Fixes: 514aee66

 ("RDMA: Globally allocate and release QP memory")
Link: https://lore.kernel.org/r/20211019082212.7052-1-pkushwaha@marvell.com
Acked-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Shai Malin <smalin@marvell.com>
Signed-off-by: Alok Prasad <palok@marvell.com>
Signed-off-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>