package/Config.in: fix alphabetic order

Commit ebf3a611 (package/libyuv: new package, 2015-08-11) added a
reference to the libyuv Config.in file at the wrong place. Fix that.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>