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: e2bcd8b0 ("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 <chris@disavowed.jp>
Reported-by: Doug Brown <doug@downtowndougbrown.com>
Signed-off-by: Vincent Duvert <vincent.ldev@duvert.net>
[lukas: add missing tags]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.1+
Cc: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>