Merge branch 'appletalk-small-cleanup-and-bugfix'

Yue Haibing says:

====================
appletalk: small cleanup and bugfix

v2:
- Add cover letter log

This patch series mainly fix a use-after-free bug in atalk_proc_exit.
patch 1 use remove_proc_subtree helper to simplify atalk_proc fs code,
also some other cleanup.
patch 2 add proper error cleanup path in atalk_init to fix the issue, which
based on the patch 1 because of the change of atalk_proc_exit context.
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Signed-off-by: David S. Miller <davem@davemloft.net>