README: update to latest info
README: update to latest info

Odroid-xu3 now working on u-boot 2016 and 4.1 kernel.

Signed-off-by: Armin Kuster <525edcd226fb27e7f47fbb319a38fe989c677548@gmail.com>

twoerner/meta-odroid,akuster/meta-odroid,akuster/meta-odroid,twoerner/meta-odroid,akuster/meta-odroid,akuster/meta-odroid,twoerner/meta-odroid