km: fix license string and compatible strings

As the ownership is now Hitachi Power Grids, change the license string
and adapt the compatible string in DTS files. For kmeter1.dts we
change it to "keymile,KMETER1" for now, as this is then compliant with
what is submitted to the linux kernel. All other boards don't have
a upstreamed version in linux mainline.

Signed-off-by: Holger Brunck <holger.brunck@hitachi-powergrids.com>
CC: Valentin Longchamp <valentin.longchamp@hitachi-powergrids.com>
CC: Heiko Schocher <hs@denx.de>
CC: Marek Vasut <marex@denx.de>
CC: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/dts/kmeter1-uboot.dtsi b/arch/powerpc/dts/kmeter1-uboot.dtsi
index 898fa7d..5f63994 100644
--- a/arch/powerpc/dts/kmeter1-uboot.dtsi
+++ b/arch/powerpc/dts/kmeter1-uboot.dtsi
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * ABB PGGA kmeter1 U-Boot specific Device Tree Source parts
+ * Hitachi Power Grids kmeter1 U-Boot specific Device Tree Source parts
  *
  * Copyright (C) 2020 Heiko Schocher <hs@denx.de>
  *