nfp: pass ctrl_bar pointer to nfp_net_alloc

Move setting ctrl_bar pointer to the nfp_net_alloc function,
to make sure we can parse capabilities early in the following
patch.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>