[NET]: Add probe_old_netdevs() hook.

This set of patches is a mixture of Al's work to device initialization,
and some of my own to complete it for all the ether, tr, sbni, and loopback
devices.

The first patch adds the hook for converting old driver initialization
code over to dynamic allocation.

This part extracted from Al viro's set of net driver changes for ethertap.

drivers/net/Space.c

@@ -382,6 +382,12 @@ static int __init ethif_probe(struct net_device *dev)
 	return -ENODEV;
 }
 
+/*  Statically configured drivers -- order matters here. */
+void probe_old_netdevs(void)
+{
+
+}
+
 #ifdef CONFIG_SDLA
 extern int sdla_init(struct net_device *);
 static struct net_device sdla0_dev = {

include/linux/netdevice.h

@@ -498,6 +498,7 @@ extern struct net_device		loopback_dev;		/* The loopback */
 extern struct net_device		*dev_base;		/* All devices */
 extern rwlock_t				dev_base_lock;		/* Device list lock */
 
+extern void		probe_old_netdevs(void);
 extern int			netdev_boot_setup_add(char *name, struct ifmap *map);
 extern int 			netdev_boot_setup_check(struct net_device *dev);
 extern struct net_device    *dev_getbyhwaddr(unsigned short type, char *hwaddr);

net/core/dev.c

@@ -3098,6 +3098,8 @@ static int __init net_dev_init(void)
 
 	dev_boot_phase = 0;
 
+	probe_old_netdevs();
+
 	open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
 	open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);