HAL support for 8s watchdog

Marlin/src/HAL/LINUX/watchdog.cpp

@@ -27,6 +27,8 @@
 
 #include "watchdog.h"
 
+#define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
+
 void watchdog_init() {}
 void HAL_watchdog_refresh() {}
 

Marlin/src/HAL/LINUX/watchdog.h

@@ -21,7 +21,5 @@
  */
 #pragma once
 
-#define WDT_TIMEOUT   4000000 // 4 second timeout
-
 void watchdog_init();
 void HAL_watchdog_refresh();