RDMA: Fix allocation failure on pointer pd

The null check on an allocation failure on pd is currently checking
if pd is non-null rather than null. Fix this by adding the missing !
operator.

Fixes: 21a428a0 ("RDMA: Handle PD allocations by IB/core")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hns/hns_roce_hw_v1.c

@@ -745,7 +745,7 @@ static int hns_roce_v1_rsv_lp_qp(struct hns_roce_dev *hr_dev)
 
 	ibdev = &hr_dev->ib_dev;
 	pd = rdma_zalloc_drv_obj(ibdev, ib_pd);
-	if (pd)
+	if (!pd)
 		goto alloc_mem_failed;
 
 	pd->device  = ibdev;