nfp: send control message when MAC representors are created

The firmware expects a MAC_REPR control message when a MAC representor
is created. The driver should expect a PORTMOD message to follow which
will provide the link states of the physical port associated with the MAC
representor.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>