IB/core: Use PTR_ERR_OR_ZERO()

Fix ptr_ret.cocci warnings:
drivers/infiniband/core/uverbs_cmd.c:1156:1-3: WARNING: PTR_ERR_OR_ZERO can be used

Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci
Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -1145,10 +1145,7 @@ int ib_uverbs_ex_create_cq(struct ib_uverbs_file *file,
 			min(ucore->inlen, sizeof(cmd)),
 			ib_uverbs_ex_create_cq_cb, NULL);
 
-	if (IS_ERR(obj))
-		return PTR_ERR(obj);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(obj);
 }
 
 ssize_t ib_uverbs_resize_cq(struct ib_uverbs_file *file,