net: Do not return value from init_dummy_netdev()

init_dummy_netdev() always returns zero and all the callers do not check
the returned value. Set the function to not return value, as it is not
really used today.
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240205103022.440946-1-amcohen@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/netdevice.h

@@ -3198,7 +3198,7 @@ static inline void unregister_netdevice(struct net_device *dev)
 int netdev_refcnt_read(const struct net_device *dev);
 void free_netdev(struct net_device *dev);
 void netdev_freemem(struct net_device *dev);
-int init_dummy_netdev(struct net_device *dev);
+void init_dummy_netdev(struct net_device *dev);
 
 struct net_device *netdev_get_xmit_slave(struct net_device *dev,
 					 struct sk_buff *skb,

net/core/dev.c

@@ -10345,7 +10345,7 @@ EXPORT_SYMBOL(register_netdevice);
  *	that need to tie several hardware interfaces to a single NAPI
  *	poll scheduler due to HW limitations.
  */
-int init_dummy_netdev(struct net_device *dev)
+void init_dummy_netdev(struct net_device *dev)
 {
 	/* Clear everything. Note we don't initialize spinlocks
 	 * are they aren't supposed to be taken by any of the
@@ -10373,8 +10373,6 @@ int init_dummy_netdev(struct net_device *dev)
 	 * because users of this 'device' dont need to change
 	 * its refcount.
 	 */
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(init_dummy_netdev);