samples: led: pwm: Add overlay for stm32f4_disco board

Add Devicetree overlay for sample drivers/led/pwm for stm32f4_disco
board board to disable gpio leds node.

Signed-off-by: Yishai Jaffe <[email protected]>

Author: yishai1999

samples/drivers/led/pwm/boards/stm32f4_disco.overlay

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2023 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	leds {
+		status = "disabled";
+	};
+};