tests: pwm: sam0: Added overlay file for pwm starting

 - Added the overlay files for testing the same54_xpro boards
  for the pwm_gpio_loopback test.

Signed-off-by: Muhammed Asif <[email protected]>

Author: ghostMan-pac

tests/drivers/pwm/pwm_gpio_loopback/boards/same54_xpro.conf

@@ -0,0 +1 @@
+CONFIG_GPIO=y

tests/drivers/pwm/pwm_gpio_loopback/boards/same54_xpro.overlay

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2025 Muhammed Asif
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Test requires jumper between:
+ *  - PA04 -- PA05
+ */
+
+/ {
+	zephyr,user {
+		pwms = <&tc0 1 PWM_MSEC(2)>;
+		gpios = <&porta 4 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&tc0 {
+	status = "okay";
+	compatible = "atmel,sam0-tc-pwm";
+	/* Gives a maximum period of 1.1s for 120MHz main clock */
+	prescaler = <4>;
+	#pwm-cells = <2>;
+
+	pinctrl-0 = <&tc0_default>;
+	pinctrl-names = "default";
+
+	channels = <2>;
+	counter-size = <32>;
+};
+
+&pinctrl {
+	tc0_default: tc0_default {
+		group1 {
+			pinmux = <PA5E_TC0_WO1>;
+		};
+	};
+};