drm_hwcomposer: Pull CI check into dedicated script

This will be useful for adding more functionality to it. It's not very
practical to script inside the yml.

Change-Id: I71aa6b40d282f750eb9bce65dd2cfd9e2828905b
Signed-off-by: Sean Paul <seanpaul@chromium.org>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 24c4a0a..d0175f0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -7,12 +7,9 @@
 stages:
   - style
 
-clang-format:
+checkstyle:
   stage: style
-  script:
-    - git fetch https://gitlab.freedesktop.org/drm-hwcomposer/drm-hwcomposer.git
-    - git diff -U0 --no-color FETCH_HEAD...HEAD -- | clang-format-diff-5.0 -p 1 -style=file > format-fixup.patch
-    - if [ -s format-fixup.patch ]; then cat format-fixup.patch && exit 1; fi
+  script: "./.gitlab-ci-checkcommit.sh"
   artifacts:
     when: on_failure
     paths: