phase1: kmodprepare: add apk compat

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>

phase1/master.cfg

@@ -1307,6 +1307,7 @@ def prepareFactory(target):
  command=[
  "rsync",
  "--include=/kmod-*.ipk",
+ "--include=/kmod-*.apk",
  "--exclude=*",
  "-va",
  Interpolate(