tf-static-checks.yaml: block job until tf-ci-gateway job finishes

Although block and non-block scenarios do the same task, blocking the
tf-static-checks job until tf-ci-gateway finishes is a better way to
keep track of triggered tf-ci-gateway job, as seen in [1].

[1] https://ci.staging.trustedfirmware.org/view/TF-A/job/lsandov1-tf-static-checks/40/

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I3f86caa51f926203a529574aea9df1b823f6fe1e
1 file changed