udp_tunnel: Fix end of loop test in udp_tunnel_nic_unregister()

stable inclusion
from stable-v5.10.103
commit 1c5912895545038aebce0596209e5c95f4fc8dfb
bugzilla: https://gitee.com/openeuler/kernel/issues/I56NE7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1c5912895545038aebce0596209e5c95f4fc8dfb



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

commit de7b2efa upstream.

This test is checking if we exited the list via break or not.  However
if it did not exit via a break then "node" does not point to a valid
udp_tunnel_nic_shared_node struct.  It will work because of the way
the structs are laid out it's the equivalent of
"if (info->shared->udp_tunnel_nic_info != dev)" which will always be
true, but it's not the right way to test.

Fixes: 74cc6d18 ("udp_tunnel: add the ability to share port tables")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>