Fix flash_safe_execute timeout under FreeRTOS

In some cases, the flash lockout task can start on the wrong core and
not have time to move to the correct core before exit is called. This
causes a timeout as the exit function is looking at the wrong core when
checking for the lockout task.

Author: jackwilsdon

src/rp2_common/pico_flash/flash.c

@@ -142,16 +142,14 @@ static int default_enter_safe_zone_timeout_ms(__unused uint32_t timeout_ms) {
         // it only prevents the other core from also entering a critical section.
         // Therefore, we must do our own handshake which starts a task on the other core and have it disable interrupts
         uint core_num = get_core_num();
-        // create at low priority
+        // create at low priority on other core
         TaskHandle_t task_handle;
-        if (pdPASS != xTaskCreate(flash_lockout_task, "flash lockout", configMINIMAL_STACK_SIZE, (void *)core_num, 0, &task_handle)) {
+        if (pdPASS != xTaskCreateAffinitySet(flash_lockout_task, "flash lockout", configMINIMAL_STACK_SIZE, (void *)core_num, 0, 1u << (core_num ^ 1), &task_handle)) {
             return PICO_ERROR_INSUFFICIENT_RESOURCES;
         }
         lockout_state[core_num] = FREERTOS_LOCKOUT_LOCKER_WAITING;
         __sev();
-        // bind to other core
-        vTaskCoreAffinitySet(task_handle, 1u << (core_num ^ 1));
-        // and make it super high priority
+        // make it super high priority
         vTaskPrioritySet(task_handle, configMAX_PRIORITIES -1);
         absolute_time_t until = make_timeout_time_ms(timeout_ms);
         while (lockout_state[core_num] != FREERTOS_LOCKOUT_LOCKEE_READY && !time_reached(until)) {