dt-bindings: can: tcan4x5x: Add DT bindings for TCAN4x5X driver

DT binding documentation for TI TCAN4x5x driver.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/tcan4x5x.txt

+Texas Instruments TCAN4x5x CAN Controller
+================================================
+
+This file provides device node information for the TCAN4x5x interface contains.
+
+Required properties:
+	- compatible: "ti,tcan4x5x"
+	- reg: 0
+	- #address-cells: 1
+	- #size-cells: 0
+	- spi-max-frequency: Maximum frequency of the SPI bus the chip can
+			     operate at should be less than or equal to 18 MHz.
+	- data-ready-gpios: Interrupt GPIO for data and error reporting.
+	- device-wake-gpios: Wake up GPIO to wake up the TCAN device.
+
+See Documentation/devicetree/bindings/net/can/m_can.txt for additional
+required property details.
+
+Optional properties:
+	- reset-gpios: Hardwired output GPIO. If not defined then software
+		       reset.
+	- device-state-gpios: Input GPIO that indicates if the device is in
+			      a sleep state or if the device is active.
+
+Example:
+tcan4x5x: tcan4x5x@0 {
+		compatible = "ti,tcan4x5x";
+		reg = <0>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		spi-max-frequency = <10000000>;
+		bosch,mram-cfg = <0x0 0 0 32 0 0 1 1>;
+		data-ready-gpios = <&gpio1 14 GPIO_ACTIVE_LOW>;
+		device-state-gpios = <&gpio3 21 GPIO_ACTIVE_HIGH>;
+		device-wake-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpio1 27 GPIO_ACTIVE_LOW>;
+};