style: Don't include diff context in git style hook

The git style hook currently includes a few lines of diff context when
determining changed regions. This is undesirable as this triggers
false positives when modifying existing files with a lot of style
violations. This change sets the amount of context to 0, which is the
default value when requesting staged regions from the git helper.

Change-Id: Ibe03123e329ea0241281e104183a68d6c495b190
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>

util/git-pre-commit.py

@@ -58,7 +58,6 @@ git = GitRepo()
 
 opts = {}
 repo_base = git.repo_base()
-context = 8
 ui = StdioUI()
 
 os.chdir(repo_base)
@@ -68,7 +67,7 @@ for status, fname in git.status(filter="MA", cached=True):
     if args.verbose:
         print "Checking %s..." % fname
     if status == "M":
-        regions = git.staged_regions(fname, context=context)
+        regions = git.staged_regions(fname)
     else:
         regions = all_regions