bonding: debugfs and network namespaces are incompatible

The bonding debugfs support has been broken in the presence of network
namespaces since it has been added.  The debugfs support does not handle
multiple bonding devices with the same name in different network
namespaces.

I haven't had any bug reports, and I'm not interested in getting any.
Disable the debugfs support when network namespaces are enabled.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>