HAL support for 8s watchdog

Marlin/src/HAL/TEENSY35_36/watchdog.cpp

@@ -27,9 +27,11 @@
 
 #include "watchdog.h"
 
+#define WDT_TIMEOUT_MS TERN(WATCHDOG_DURATION_8S, 8000, 4000) // 4 or 8 second timeout
+
 void watchdog_init() {
   WDOG_TOVALH = 0;
-  WDOG_TOVALL = 4000;
+  WDOG_TOVALL = WDT_TIMEOUT_MS;
   WDOG_STCTRLH = WDOG_STCTRLH_WDOGEN;
 }