Snowball: Pin u-boot for the stable-blob build

The stable-blob (landing-snowball.xml) build can not use the latest
u-boot since it expects support for device tree. The stable-blob
build is based on the igloocommunity 3.4 kernel and it does not
have support for device tree.

Change-Id: Ica31da1468e5e55be022be47965a7d1755df0d47
Signed-off-by: Patrik Ryd <patrik.ryd@linaro.org>
1 file changed