ARM: shmobile: r8a7779: fixup dtsi typo

r8a7779 is not r8a7740 chip
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7779.dtsi

 /*
- * Device Tree Source for Renesas r8a7740
+ * Device Tree Source for Renesas r8a7779
  *
  * Copyright (C) 2013 Renesas Solutions Corp.
  * Copyright (C) 2013 Simon Horman