sh: r2dplus: Enable OF control

Enable OF control for SH4 R2Dplus board. This is necessary, because
the PCI uclass is designed in a way that makes it depend on DT and
disallows instanciating devices without DT (e.g. with platdata).

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/sh/dts/Makefile b/arch/sh/dts/Makefile
new file mode 100644
index 0000000..e423bfd
--- /dev/null
+++ b/arch/sh/dts/Makefile
@@ -0,0 +1,12 @@
+dtb-y += sh7751-r2dplus.dtb
+
+targets += $(dtb-y)
+
+# Add any required device tree compiler flags here
+DTC_FLAGS +=
+
+PHONY += dtbs
+dtbs: $(addprefix $(obj)/, $(dtb-y))
+	@:
+
+clean-files := *.dtb *_HS