bindings: interrupt-controller: Add .yaml file for irqsteer channel node

This commit adds a new DTS binding used to specify an IRQSTEER
channel node.

Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>

dts/bindings/interrupt-controller/nxp,irqsteer-channel.yaml

@@ -0,0 +1,19 @@
+description: i.MX IRQ_STEER channel
+
+compatible: "nxp,irqsteer-channel"
+
+include: [interrupt-controller.yaml, base.yaml]
+
+properties:
+  "#interrupt-cells":
+    const: 1
+
+  interrupt-channel:
+    type: int
+    required: true
+
+  reg:
+    required: true
+
+interrupt-cells:
+  - irq