rockchip: dts: rk3399-puma: add DTS for the DDR3-1866 timing

This adds the DDR3-1866 timing via its own DTS and wires it up.  This
(currently) is not the default timing for the RK3399-Q7 and should be
selected explicitly via the config (CONFIG_DEFAULT_DEVICE_TREE).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/dts/rk3399-puma-ddr1866.dts b/arch/arm/dts/rk3399-puma-ddr1866.dts
new file mode 100644
index 0000000..4eec8e7
--- /dev/null
+++ b/arch/arm/dts/rk3399-puma-ddr1866.dts
@@ -0,0 +1,11 @@
+/*
+ * (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
+ *
+ * SPDX-License-Identifier:     GPL-2.0+	X11
+ */
+
+/dts-v1/;
+
+#include "rk3399-puma.dtsi"
+#include "rk3399-sdram-ddr3-1866.dtsi"
+