openvswitch: switch from WARN to pr_warn

stable inclusion
from stable-v5.10.153
commit 79631daa5a5166c6aa4e25f447e8c08ee030637a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=79631daa5a5166c6aa4e25f447e8c08ee030637a



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

[ Upstream commit fd954cc1 ]

As noted by Paolo Abeni, pr_warn doesn't generate any splat and can still
preserve the warning to the user that feature downgrade occurred.  We
likely cannot introduce other kinds of checks / enforcement here because
syzbot can generate different genl versions to the datapath.

Reported-by:  <syzbot+31cde0bef4bbf8ba2d86@syzkaller.appspotmail.com>
Fixes: 44da5ae5 ("openvswitch: Drop user features if old user space attempted to create datapath")
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Aaron Conole <aconole@redhat.com>
Acked-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lipeng Sang <sanglipeng1@jd.com>