kernel: modules: appletalk: add for Netatalk v4

kernel: modules: appletalk: add for Netatalk v4

Netatalk v4 reintroduces AppleTalk and this module is required for
layer 3 protocol support.

Module was removed in kernel 4.14 for OpenWrt 18.06 (commmit
14a0131, 22/02/2018). At the time nothing used it as Netatalk v3
did not support AppleTalk.

Not building ipddp feature/module like it was in the past, as
recommended by upstream Netatalk maintainers.

Signed-off-by: Antonio Pastor <antonio.pastor@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16979
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>