ARM: dts: rmobile: Build -u-boot variants of DTs

Build the -u-boot variants of the device trees so they can be included
in Multi-DTB fitImage, which in turn allows us to build single U-Boot
image for multiple boards.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>

arch/arm/dts/Makefile

@@ -455,14 +455,14 @@ dtb-$(CONFIG_MX7) += imx7-colibri.dtb \
 dtb-$(CONFIG_ARCH_MX7ULP) += imx7ulp-evk.dtb
 
 dtb-$(CONFIG_RCAR_GEN3) += \
-	r8a7795-h3ulcb.dtb \
-	r8a7795-salvator-x.dtb \
-	r8a7796-m3ulcb.dtb \
-	r8a7796-salvator-x.dtb \
-	r8a77965-salvator-x.dtb \
-	r8a77970-eagle.dtb \
-	r8a77990-ebisu.dtb \
-	r8a77995-draak.dtb
+	r8a7795-h3ulcb-u-boot.dtb \
+	r8a7795-salvator-x-u-boot.dtb \
+	r8a7796-m3ulcb-u-boot.dtb \
+	r8a7796-salvator-x-u-boot.dtb \
+	r8a77965-salvator-x-u-boot.dtb \
+	r8a77970-eagle-u-boot.dtb \
+	r8a77990-ebisu-u-boot.dtb \
+	r8a77995-draak-u-boot.dtb
 
 dtb-$(CONFIG_SOC_KEYSTONE) += keystone-k2hk-evm.dtb \
 	keystone-k2l-evm.dtb \