dmaengine: rcar-dmac: Update copyright information

Update copyright and string for Gen3.
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/sh/rcar-dmac.c

 // SPDX-License-Identifier: GPL-2.0
 /*
- * Renesas R-Car Gen2 DMA Controller Driver
+ * Renesas R-Car Gen2/Gen3 DMA Controller Driver
  *
- * Copyright (C) 2014 Renesas Electronics Inc.
+ * Copyright (C) 2014-2019 Renesas Electronics Inc.
  *
  * Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  */