Move Zephyr app into subdirectory.

app/drivers/zephyr/dts/bindings/gpio-kscan.yaml

@@ -0,0 +1,25 @@
+# Copyright (c) 2020, Pete Johanson
+# SPDX-License-Identifier: Apache-2.0
+
+description: GPIO keyboard matrix controller
+
+compatible: "gpio-kscan"
+
+include: kscan.yaml
+
+properties:
+    row-gpios:
+        type: phandle-array
+        required: true
+    col-gpios:
+        type: phandle-array
+        required: true
+    debounce-period:
+        type: int
+        default: 5
+    diode-direction:
+        type: string
+        default: row2col
+        enum:
+          - row2col
+          - col2row