app: provide in-tree board overlay

Provide an overlay to shows how to run the example-application on boards
that are part of the Zephyr tree. Sometimes initial development is
performed on dev-kits, so it can be useful. A different vendor than the
one used for the custom board (Nordic) has been chosen to show
application portability.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

Author: gmarull

app/boards/nucleo_f302r8.overlay

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* This devicetree overlay file will be automatically picked by the Zephyr
+ * build system when building the sample for the nucleo_f302r8 board. It shows
+ * how the example-application can be built on sample boards already provided
+ * by Zephyr.
+ */
+
+/ {
+	examplesensor0: examplesensor_0 {
+		compatible = "zephyr,examplesensor";
+		label = "EXAMPLESENSOR_0";
+		input-gpios = <&gpioc 13 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+	};
+};
+
+&gpioc {
+	status = "okay";
+};