samples: boards: Add MCO support for nucleo_wl55jc

Added overlay and modified sample.yaml to support the nucleo_wl55jc
board in the MCO example.

Signed-off-by: Martdur <martin.durietz@gmail.com>

Author: Martdur

samples/boards/st/mco/boards/nucleo_wl55jc.overlay

@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2025 STMicroelectronics
+ */
+
+/* Enable the clock we are going to output */
+&clk_lse
+{
+	status = "okay";
+};
+
+&mco1
+{
+	status = "okay";
+	clocks = <&rcc STM32_SRC_LSE MCO1_SEL(MCO_SEL_LSE)>;
+	prescaler = <MCO1_PRE(MCO_PRE_DIV_1)>;
+	pinctrl-0 = <&rcc_mco_pa8>;
+	pinctrl-names = "default";
+};

samples/boards/st/mco/sample.yaml

@@ -9,6 +9,7 @@ tests:
       - stm32f746g_disco
       - nucleo_u5a5zj_q
       - nucleo_wba55cg
+      - nucleo_wl55jc
     integration_platforms:
       - stm32f746g_disco
     tags: board