dim: update copyright year and authorship

Considering the git stats on the script, seems fair to add myself as an
author.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

dim

 #!/bin/bash
 
-# Copyright © 2012-2015 Intel Corporation
+# Copyright © 2012-2016 Intel Corporation
 #
 # Permission is hereby granted, free of charge, to any person obtaining a
 # copy of this software and associated documentation files (the "Software"),
@@ -23,6 +23,7 @@
 #
 # Authors:
 #    Daniel Vetter <daniel.vetter@ffwll.ch>
+#    Jani Nikula <jani.nikula@intel.com>
 
 # drm-intel-next maintainer script