Ansuel reported, that with `USE_APK=y` there are no kmods available in
the build artifacts, so lets fix it by extending the rsync's include
pattern with the `apk` suffix to make it future proof.
Reported-by: Christian Marangi <ansuelsmth@gmail.com> Signed-off-by: Petr Štetiar <ynezz@true.cz>