By default, the checkpatch script requires that commit references
included in commit messages follow a predefined format. Github
merge commits do not follow this convention, causing the code
style test to fail when a new pull request is created.

This patch adds the ignore GIT_COMMIT_ID option to the checkpatch
parameters. This flag indicates the tool to ignore the commit
message format.

Change-Id: I37133cc5cf803f664b8ff00f62d458b39f06918c