[MCUX-85656] Fixing cpp linkage issue

Cpp linkage issue would happen if a cpp file do below include:
include "FreeRTOS.h"
include "fsl_debug_console.h"

system_*.h is cpp capable but FreeRTOS.h is no more cpp capable since FreeRTOS#1047

The change aims to align FreeRTOS-side declaration with CMSIS/device declaration.

Signed-off-by: Gatien Chapon <gatien.chapon@nxp.com>

Author: chapongatien

template/FreeRTOSConfig.h

@@ -29,6 +29,12 @@
 #ifndef FREERTOS_CONFIG_H
 #define FREERTOS_CONFIG_H
 
+/* *INDENT-OFF* */
+#ifdef __cplusplus
+    extern "C" {
+#endif
+/* *INDENT-ON* */
+
 #if defined(__ICCARM__)||defined(__CC_ARM)||defined(__GNUC__)
     #include <stdint.h>
     extern uint32_t SystemCoreClock;
@@ -95,4 +101,10 @@
     #endif
 #endif
 
+/* *INDENT-OFF* */
+#ifdef __cplusplus
+    }
+#endif
+/* *INDENT-ON* */
+
 #endif /* FREERTOS_CONFIG_H */