rtnetlink: Move nesting cancellation rollback to proper function

Make rtnl_fill_vf() cancel the vfinfo attribute on error instead of the
inner rtnl_fill_vfinfo(), as it is the function that starts it.

Signed-off-by: Gal Pressman <gal@nvidia.com>
Link: https://lore.kernel.org/r/20230716072440.2372567-1-gal@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>