The header add checker only handles added header, which makes it miss
issues when a header is renamed. Fix it.
Fixes: 8fffab46b8 ("utils: checkstyle.py: Add header add checker")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>