Fix nsh_archinitialize return value

configs/stm32f4discovery/src/stm32_nsh.c

@@ -64,11 +64,13 @@
 
 int nsh_archinitialize(void)
 {
-#ifndef CONFIG_BOARD_INITIALIZE
+#ifdef CONFIG_BOARD_INITIALIZE
+  /* Board initialization already performed by board_initialize() */
+
+  return OK;
+#else
   /* Perform board-specific initialization */
 
-  (void)stm32_bringup();
+  return stm32_bringup();
 #endif
-
-  return OK;
 }