xsk: remove unnecessary assignment

mainline inclusion
from mainline-4.20
commit a29c8bb640ca
category: bugfix
bugzilla: 6111
CVE: NA

-------------------------------------------------

Since xdp_umem_query() was added one assignment of bpf.command was
missed from cleanup. Removing the assignment statement.

Fixes: 84c6b868 ("xsk: don't allow umem replace at stack level")
Signed-off-by: NPrashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: NBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NKeefe LIU <liuqifa@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/xdp/xdp_umem.c

@@ -71,8 +71,6 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
 	if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_async_xmit)
 		return force_zc ? -EOPNOTSUPP : 0; /* fail or fallback */
 
-	bpf.command = XDP_QUERY_XSK_UMEM;
-
 	rtnl_lock();
 	err = xdp_umem_query(dev, queue_id);
 	if (err) {