maemo/gtk+2.0-maemo: fix APKBUILD to get patches actually applied

It seems after some changes either to default_prepare or APKBUILD the trick to symlink .diff files with .patch extension to get them automatically applied no longer works. This MR changes APKBUILD to download the files with .patch extension in the first place, so that workaround can be removed. Fixes missing symbols in #402 (closed).