net/bonding: validate speed after link up

net/bonding: validate speed after link up

It's possible for the bonding driver to mistakenly reject an interface
based in it's, as yet, unnegotiated link speed and duplex. Always allow
the interface to be added to the bonding interface but require link
properties validation to succeed before slave is activated.

Fixes: 2efb58cbab6e ("bond: new link bonding library")
Signed-off-by: Eric Kinzie <ehkinzie@gmail.com>
Acked-by: Bernard Iremonger <bernard.iremonger@intel.com>