sunxi-board-fex: Fix recipe versioning

Git repository sunxi-boards is not versioned. For now there is no
tracking of a git revision in the recipe. This patch fixes it. Related
discussion:
http://article.gmane.org/gmane.comp.handhelds.openembedded/62130

Signed-off-by: Tomas Novotny <novotny@rehivetech.com>
sunxi-board-fex: trivial: Remove invalid comment

Signed-off-by: Tomas Novotny <novotny@rehivetech.com>