tests: drivers: uart: uart_basic_api: add support for nucleo_h753zi

- add .overlay with appropriate configurations for
  nucleo_h753zi
- update testcase.yaml file for CI testing

Signed-off-by: Fabrice DJIATSA <[email protected]>

Author: djiatsaf-st

tests/drivers/uart/uart_basic_api/boards/nucleo_h753zi.overlay

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2025 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+dut: &usart2 {
+	pinctrl-0 = <&usart2_tx_pd5 &usart2_rx_pd6>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};

tests/drivers/uart/uart_basic_api/testcase.yaml

@@ -16,7 +16,9 @@ tests:
     filter: CONFIG_UART_CONSOLE
     harness: keyboard
     arch_allow: arm
-    platform_allow: nucleo_h743zi
+    platform_allow:
+      - nucleo_h743zi
+      - nucleo_h753zi
     integration_platforms:
       - nucleo_h753zi
     extra_args: DTC_OVERLAY_FILE="boards/nucleo_h743zi.overlay"