tests: gpio: boards: add overlay for GPIO test driver

Added the xg29_rb4412a.overlay for GPIO API 1-pin
This overlay sets the configuration
needed to validate the GPIO driver on the
xg29_rb4412a board during test execution.

Signed-off-by: S Mohamed Fiaz <[email protected]>

Author: fimohame

tests/drivers/gpio/gpio_api_1pin/boards/xg29_rb4412a.overlay

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2025 Silicon Laboratories Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		led0 = &led0;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		led0: led_0 {
+			gpios = <&gpioc 7 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+&gpioc {
+	status = "okay";
+};