tests: drivers: pwm: Add support pwm_loopback for ek_ra8p1

Add support test app pwm_loopback for Renesas ek_ra8p1

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

tests/drivers/pwm/pwm_loopback/boards/ek_ra8p1_r7ka8p1kflcac_cm85.overlay

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2025 Renesas Electronics Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/pwm/pwm.h>
+#include <zephyr/dt-bindings/pwm/ra_pwm.h>
+
+/ {
+	pwm_loopback_0 {
+		compatible = "test-pwm-loopback";
+		/* first index must be a 32-Bit timer */
+		pwms = <&pwm1 0 0 PWM_POLARITY_NORMAL>,
+			<&pwm2 0 0 PWM_POLARITY_NORMAL>;
+	};
+};
+
+&pinctrl {
+	pwm2_default: pwm2_default {
+		group1 {
+			/* GTIOC2A */
+			psels = <RA_PSEL(RA_PSEL_GPT1, 1, 3)>;
+		};
+	};
+};
+
+&pwm2 {
+	pinctrl-0 = <&pwm2_default>;
+	pinctrl-names = "default";
+	interrupts = <94 1>, <95 1>;
+	interrupt-names = "gtioca", "overflow";
+	status = "okay";
+};