tests: drivers: pwm: pwm_api: add nucleo_u385rg_q

PWM API test were not available for the nucleo_u385rg_q board.
Added the nucleo_u385rg_q board overlay to the pwm_api test.

Signed-off-by: Richard Skriwanek <richy@fnc.at>
diff --git a/tests/drivers/pwm/pwm_api/boards/nucleo_u385rg_q.overlay b/tests/drivers/pwm/pwm_api/boards/nucleo_u385rg_q.overlay
new file mode 100644
index 0000000..de44f1a
--- /dev/null
+++ b/tests/drivers/pwm/pwm_api/boards/nucleo_u385rg_q.overlay
@@ -0,0 +1,21 @@
+/*
+ * SPDX-FileCopyrightText: Copyright The Zephyr Project Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		pwm-test = &pwm2;
+	};
+};
+
+&timers2 {
+	st,prescaler = <10000>;
+	status = "okay";
+
+	pwm2: pwm {
+		pinctrl-0 = <&tim2_ch3_pb10>;
+		pinctrl-names = "default";
+		status = "okay";
+	};
+};