sdk: run make prereq in tests

Add the tests from packages.git ci[0] to docker test.

[0]: a6d5b5d1c1

Signed-off-by: Paul Spooren <mail@aparcar.org>

.gitlab/ci/sdk.yml

@@ -21,6 +21,11 @@ test-sdk:
   stage: test
   script:
     - cd ~/openwrt
+    - touch .config
+    - make prepare-tmpinfo scripts/config/conf
+    - ./scripts/config/conf --defconfig=.config Config.in
+    - make prereq
+    - rm .config
     - make defconfig
     - ./scripts/feeds update base
     - ./scripts/feeds install busybox