net/mlx4: Postpone the registration of net_device

The mlx4 network driver was registered in the context of the 'add'
function of the core driver (called when HW should be registered).
This makes the netdev event NETDEV_REGISTER to be sent in a context
where the answer to get_protocol_dev() callback returns NULL. This may
be confusing to listeners of netdev events.
This patch is a preparation to the patch that implements the
get_netdev() callback in the IB/mlx4 driver.

Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

include/linux/mlx4/driver.h

@@ -59,6 +59,7 @@ struct mlx4_interface {
 	void			(*event) (struct mlx4_dev *dev, void *context,
 					  enum mlx4_dev_event event, unsigned long param);
 	void *			(*get_dev)(struct mlx4_dev *dev, void *context, u8 port);
+	void			(*activate)(struct mlx4_dev *dev, void *context);
 	struct list_head	list;
 	enum mlx4_protocol	protocol;
 	int			flags;