ASoc: Add Texas Instruments TAS2562 amplifier binding

Add the DT binding for the TAS2562 amplifier.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20191008181517.5332-1-dmurphy@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/tas2562.txt

+Texas Instruments TAS2562 Smart PA
+
+The TAS2562 is a mono, digital input Class-D audio amplifier optimized for
+efficiently driving high peak power into small loudspeakers.
+Integrated speaker voltage and current sense provides for
+real time monitoring of loudspeaker behavior.
+
+Required properties:
+ - #address-cells  - Should be <1>.
+ - #size-cells     - Should be <0>.
+ - compatible:	   - Should contain "ti,tas2562".
+ - reg:		   - The i2c address. Should be 0x4c, 0x4d, 0x4e or 0x4f.
+ - ti,imon-slot-no:- TDM TX current sense time slot.
+
+Optional properties:
+- interrupt-parent: phandle to the interrupt controller which provides
+                    the interrupt.
+- interrupts: (GPIO) interrupt to which the chip is connected.
+- shut-down: GPIO used to control the state of the device.
+
+Examples:
+tas2562@4c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "ti,tas2562";
+        reg = <0x4c>;
+
+        interrupt-parent = <&gpio1>;
+        interrupts = <14>;
+
+	shut-down = <&gpio1 15 0>;
+        ti,imon-slot-no = <0>;
+};
+