gitlint: do not start with subsys:

Commit messages should not start with literal "subsys:", instead, spell
out the actual subsystem name.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/scripts/gitlint/zephyr_commit_rules.py b/scripts/gitlint/zephyr_commit_rules.py
index bf0a8e7..fc7309b 100644
--- a/scripts/gitlint/zephyr_commit_rules.py
+++ b/scripts/gitlint/zephyr_commit_rules.py
@@ -93,7 +93,7 @@
     def validate(self, title, _commit):
         regex = self.options['regex'].value
         pattern = re.compile(regex, re.UNICODE)
-        violation_message = "Title does not follow [subsystem]: [subject]"
+        violation_message = "Title does not follow [subsystem]: [subject] (and should not start with literal subsys:)"
         if not pattern.search(title):
             return [RuleViolation(self.id, violation_message, title)]