Instead of starting up reprs assuming that there is link, only respond
to the link state reported by firmware.

Furthermore, ensure link is down after repr netdevs are created.
Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>