freertos: Add a small additional stack when optimization set to None

Fix for occasional crash on startup when DPORT task overwrites its stack during
context switch, otherwise.

components/freertos/include/freertos/FreeRTOSConfig.h

@@ -189,7 +189,7 @@ int xt_clock_freq(void) __attribute__((deprecated));
 
 /* with optimizations disabled, scheduler uses additional stack */
 #if CONFIG_COMPILER_OPTIMIZATION_NONE
-#define configSTACK_OVERHEAD_OPTIMIZATION 256
+#define configSTACK_OVERHEAD_OPTIMIZATION 320
 #else
 #define configSTACK_OVERHEAD_OPTIMIZATION 0
 #endif