arm: dts: Create common rz-g2-beacon-u-boot file

The rzg2_beacon_defconfig creates an image for RZ/G2[MNH] and
as such creates three different device trees and each of them
have a corresponding -u-boot.dtsi file which are basically
copies of each other.  Create a common include file to be
referenced by each of the respective board-u-boot.dtsi files
to reduce duplicate code and simplify support going forward.
This also restores some lost functionality from the device
tree re-sync and updates the MAINTAINER file to include all
beacon-renesom device tree files.

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/board/beacon/beacon-rzg2m/MAINTAINERS b/board/beacon/beacon-rzg2m/MAINTAINERS
index 77c4057..f8042bb 100644
--- a/board/beacon/beacon-rzg2m/MAINTAINERS
+++ b/board/beacon/beacon-rzg2m/MAINTAINERS
@@ -4,3 +4,13 @@
 F:	board/beacon/beacon-rzg2m/
 F:	include/configs/beacon-rzg2m.h
 F:	configs/rzg2_beacon_defconfig
+F:	arch/arm/dts/beacon-renesom-baseboard.dtsi
+F:	arch/arm/dts/beacon-renesom-som.dtsi
+F:	arch/arm/dts/r8a774a1-beacon-rzg2m-kit.dts
+F:	arch/arm/dts/r8a774b1-beacon-rzg2n-kit.dts
+F:	arch/arm/dts/r8a774e1-beacon-rzg2h-kit.dts
+F:	arch/arm/dts/r8a774a1-beacon-rzg2m-kit-u-boot.dtsi
+F:	arch/arm/dts/r8a774b1-beacon-rzg2n-kit-u-boot.dtsi
+F:	arch/arm/dts/r8a774e1-beacon-rzg2h-kit-u-boot.dtsi
+F:	arch/arm/dts/rz-g2-beacon-u-boot.dtsi
+