Suppress warnings for unused parameters passed.

vApplicationStackOverflowHook( TaskHandle_t xTask __attribute__((unused)), portCHAR *pcTaskName __attribute__((unused)) )
add unused attributes to suppress compiler warnings.

Author: feilipu

src/variantHooks.cpp

@@ -194,7 +194,7 @@ void vApplicationMallocFailedHook( void )
    This routine will never return.
    This routine is referenced in the task.c file of FreeRTOS as an extern.
 \*---------------------------------------------------------------------------*/
-void vApplicationStackOverflowHook( TaskHandle_t xTask, portCHAR *pcTaskName )
+void vApplicationStackOverflowHook( TaskHandle_t xTask __attribute__((unused)), portCHAR *pcTaskName __attribute__((unused)) )
 {
 #if defined(__AVR_ATmega640__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)  // Arduino Mega with 2560
 	DDRB  |= _BV(DDB7);