dt-bindings: gpio: lsi,zevio-gpio: convert to dtschema

Convert Zevio GPIO Controller from text to dtschema.
Adding `interrupts` property fixes the following warning:
linux/out/arch/arm/boot/dts/nspire/nspire-tp.dtb: gpio@90000000:
'interrupts' does not match any of the regexes: 'pinctrl-[0-9]+'`
while executing `make dtbs_check` on Texas Instruments
nspire boards.

Signed-off-by: Pratik Farkase <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bartosz Golaszewski <[e-mail]>

Documentation/devicetree/bindings/gpio/gpio-zevio.txt

···
-Zevio GPIO controller
-
-Required properties:
-- compatible: Should be "lsi,zevio-gpio"
-- reg: Address and length of the register set for the device
-- #gpio-cells: Should be two. The first cell is the pin number and the
-  second cell is used to specify optional parameters (currently unused).
-- gpio-controller: Marks the device node as a GPIO controller.
-
-Example:
-	gpio: gpio@90000000 {
-		compatible = "lsi,zevio-gpio";
-		reg = <0x90000000 0x1000>;
-		gpio-controller;
-		#gpio-cells = <2>;
-	};

Documentation/devicetree/bindings/gpio/lsi,zevio-gpio.yaml

···
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/lsi,zevio-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Zevio GPIO controller
+
+maintainers:
+  - Pratik Farkase <[e-mail]>
+
+properties:
+  compatible:
+    items:
+      - const: lsi,zevio-gpio
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-controller: true
+
+required:
+  - compatible
+  - reg
+  - "#gpio-cells"
+  - gpio-controller
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    gpio@90000000 {
+        compatible = "lsi,zevio-gpio";
+        reg = <0x90000000 0x1000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+    };