ARM: dts: imx: Add Y Soft IOTA Draco, Hydra and Ursa boards

These are i.MX6S/DL based SBCs embedded in various Y Soft products.
All share the same board design but have slightly different HW
configuration.

Ursa
- i.MX6S SoC, 512MB RAM DDR3, 4GB eMMC, microSD
- parallel WVGA 7" LCD with touch panel
- 1x Eth (QCA8334 switch)
- USB OTG
- USB host (micro-B)

Draco
- i.MX6S SoC, 512MB RAM DDR3, 4GB eMMC, microSD
- parallel WVGA 7" LCD with touch panel
- 2x Eth (QCA8334 switch)
- USB OTG
- USB host (micro-B)
- RGB LED (I2C LP5562)
- 3.5mm audio jack + codec (LM49350)

Hydra
- i.MX6DL SoC, 2GB RAM DDR3, 4GB eMMC, microSD
- I2C OLED display, capacitive matrix keys
- 2x Eth (QCA8334 switch)
- USB OTG
- RGB LED (I2C LP5562)
- 3.5mm audio jack + codec (LM49350)
- HDMI
- miniPCIe slot

Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6dl-yapp4-hydra.dts

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2015-2018 Y Soft Corporation, a.s.
+
+/dts-v1/;
+
+#include "imx6dl.dtsi"
+#include "imx6dl-yapp4-common.dtsi"
+
+/ {
+	model = "Y Soft IOTA Hydra i.MX6DualLite board";
+	compatible = "ysoft,imx6dl-yapp4-hydra", "fsl,imx6dl";
+
+	memory@10000000 {
+		device_type = "memory";
+		reg = <0x10000000 0x80000000>;
+	};
+};
+
+&gpio_oled {
+	status = "okay";
+};
+
+&hdmi {
+	status = "okay";
+};
+
+&i2c3 {
+	status = "okay";
+};
+
+&leds {
+	status = "okay";
+};
+
+&oled {
+	status = "okay";
+};
+
+&pcie {
+	status = "okay";
+};
+
+&reg_pcie {
+	status = "okay";
+};
+
+&usdhc3 {
+	status = "okay";
+};