gitlab-ci: Add pyelftools to the binman testsuite section

We need pyelftools here to run rather than skip some tests.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2edc380..b919eaf 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -172,6 +172,9 @@
   tags: [ 'all' ]
   stage: testsuites
   script:
+    - virtualenv /tmp/venv
+    - . /tmp/venv/bin/activate
+    - pip install pyelftools
     - export UBOOT_TRAVIS_BUILD_DIR=`cd .. && pwd`/.bm-work/sandbox_spl;
       ./tools/buildman/buildman -P sandbox_spl && 
      export PYTHONPATH="${UBOOT_TRAVIS_BUILD_DIR}/scripts/dtc/pylibfdt";