tests: drivers: comparator: Add support gpio_loopback for RA8

Add support gpio_loopback to run test app on ek_ra8m1,
ek_ra8d1, mck_ra8t1

Signed-off-by: Khoa Nguyen <khoa.nguyen.xh@renesas.com>

Author: khoa-nguyen-18

tests/drivers/comparator/gpio_loopback/boards/ek_ra8d1.overlay

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/gpio/gpio.h>
+
+/ {
+	aliases {
+		test-comp = &acmphs0;
+	};
+
+	zephyr,user {
+		test-gpios = <&ioport6 0 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&acmphs_global {
+	status = "okay";
+
+	acmphs0 {
+		pinctrl-0 = <&acmphs_ivref0 &acmphs0_ivcmp0>;
+		pinctrl-names = "default";
+		interrupts = <90 12>;
+		interrupt-names = "hs";
+		reference-input-source = "ivref0";
+		compare-input-source = "ivcmp0";
+		noise-filter = <1>;
+		status = "okay";
+	};
+};

tests/drivers/comparator/gpio_loopback/boards/ek_ra8m1.overlay

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/gpio/gpio.h>
+
+/ {
+	aliases {
+		test-comp = &acmphs0;
+	};
+
+	zephyr,user {
+		test-gpios = <&ioport6 0 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&acmphs_global {
+	status = "okay";
+
+	acmphs0 {
+		pinctrl-0 = <&acmphs_ivref0 &acmphs0_ivcmp0>;
+		pinctrl-names = "default";
+		interrupts = <90 12>;
+		interrupt-names = "hs";
+		reference-input-source = "ivref0";
+		compare-input-source = "ivcmp0";
+		noise-filter = <1>;
+		status = "okay";
+	};
+};

tests/drivers/comparator/gpio_loopback/boards/mck_ra8t1.overlay

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/gpio/gpio.h>
+
+/ {
+	aliases {
+		test-comp = &acmphs0;
+	};
+
+	zephyr,user {
+		test-gpios = <&ioport6 6 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&acmphs_global {
+	status = "okay";
+
+	acmphs0 {
+		pinctrl-0 = <&acmphs_ivref0 &acmphs0_ivcmp0>;
+		pinctrl-names = "default";
+		interrupts = <90 12>;
+		interrupt-names = "hs";
+		reference-input-source = "ivref0";
+		compare-input-source = "ivcmp0";
+		noise-filter = <1>;
+		status = "okay";
+	};
+};