appletalk: Fix atalk_proc_init() return path

Add a missing return statement to atalk_proc_init so it doesn't return
-ENOMEM when successful. This allows the appletalk module to load
properly.

Fixes: e2bcd8b0ce6e ("appletalk: use remove_proc_subtree to simplify procfs code")
Link: https://www.downtowndougbrown.com/2020/08/hacking-up-a-fix-for-the-broken-appletalk-kernel-module-in-linux-5-1-and-newer/
Reported-by: Christopher KOBAYASHI <[e-mail]>
Reported-by: Doug Brown <[e-mail]>
Signed-off-by: Vincent Duvert <[e-mail]>
[lukas: add missing tags]
Signed-off-by: Lukas Wunner <[e-mail]>
Cc: [e-mail] # v5.1+
Cc: Yue Haibing <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/appletalk/atalk_proc.c

···
 				     sizeof(struct aarp_iter_state), NULL))
 		goto out;
 
+	return 0;
+
 out:
 	remove_proc_subtree("atalk", init_net.proc_net);
 	return -ENOMEM;