ARM: dts: imx6qdl-kontron-samx6i: add Kontron SMARC SoM Support

The patch adds the following interfaces according the SMARC Spec 1.1
[1] and provided schematics:
 - SMARC SPI0/1
   Note: Since Kontron still uses silicon revisions below 1.3 they have
         add a spi-nor to implement Workaround #1 of erratum ERR006282.
 - SMARC SDIO
 - SMARC LCD
 - SMARC HDMI
 - SMARC Management pins
   Note: Kontron don't route all of these pins to the i.MX6, some are
         routed to the SoM CPLD.
 - SMARC GPIO
 - SMARC CSI Camera
   Note: As specified in [1] the data lanes are shared to cover the
         csi and the parallel case. The case depends on the baseboard so
         muxing the data lanes is not part of this patch.
 - SMARC I2S
 - SMARC Watchdog
   Note: The watchdog output pin is routed to the CPLD and the SMARC
         header. The CPLD performs a reset after a 30s timeout so we
         need to enable the watchdog per default.
 - SMARC module eeprom

Due to the lack of hardware not all of these interfaces are tesetd.

[1] https://sget.org/standards/smarcSigned-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6dl-kontron-samx6i.dtsi

+// SPDX-License-Identifier: GPL-2.0 OR X11
+/*
+ * Copyright 2019 (C) Pengutronix, Marco Felsch <kernel@pengutronix.de>
+ */
+
+#include "imx6dl.dtsi"
+#include "imx6qdl-kontron-samx6i.dtsi"
+
+/ {
+	model = "Kontron SMARC sAMX6i Dual-Lite/Solo";
+	compatible = "kontron,imx6dl-samx6i", "fsl,imx6dl";
+};

arch/arm/boot/dts/imx6q-kontron-samx6i.dtsi

+// SPDX-License-Identifier: GPL-2.0 OR X11
+/*
+ * Copyright 2019 (C) Pengutronix, Marco Felsch <kernel@pengutronix.de>
+ */
+
+#include "imx6q.dtsi"
+#include "imx6qdl-kontron-samx6i.dtsi"
+#include <dt-bindings/gpio/gpio.h>
+
+/ {
+	model = "Kontron SMARC sAMX6i Quad/Dual";
+	compatible = "kontron,imx6q-samx6i", "fsl,imx6q";
+};
+
+/* Quad/Dual SoMs have 3 chip-select signals */
+&ecspi4 {
+	fsl,spi-num-chipselects = <3>;
+	cs-gpios = <&gpio3 24 GPIO_ACTIVE_HIGH>,
+		   <&gpio3 29 GPIO_ACTIVE_HIGH>,
+		   <&gpio3 25 GPIO_ACTIVE_HIGH>;
+};
+
+&pinctrl_ecspi4 {
+	fsl,pins = <
+		MX6QDL_PAD_EIM_D21__ECSPI4_SCLK 0x100b1
+		MX6QDL_PAD_EIM_D28__ECSPI4_MOSI 0x100b1
+		MX6QDL_PAD_EIM_D22__ECSPI4_MISO 0x100b1
+
+		/* SPI4_IMX_CS2# - connected to internal flash */
+		MX6QDL_PAD_EIM_D24__GPIO3_IO24 0x1b0b0
+		/* SPI4_IMX_CS0# - connected to SMARC SPI0_CS0# */
+		MX6QDL_PAD_EIM_D29__GPIO3_IO29 0x1b0b0
+		/* SPI4_CS3# - connected to  SMARC SPI0_CS1# */
+		MX6QDL_PAD_EIM_D25__GPIO3_IO25 0x1b0b0
+	>;
+};