Fix warning in gcode_D

Marlin/src/HAL/LINUX/HAL.h

 
 #define CPU_32_BIT
 
-#define F_CPU 100000000
+#define F_CPU 100000000UL
 #define SystemCoreClock F_CPU
 #include <iostream>
 #include <stdint.h>

Marlin/src/HAL/shared/Delay.h

 #endif
 
 // Delay in nanoseconds
-#define DELAY_NS(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) / 1000UL )
+#define DELAY_NS(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL) / 1000UL)
 
 // Delay in microseconds
-#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU / 1000000UL) )
+#define DELAY_US(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL))

Marlin/src/gcode/gcode_d.cpp

         // Use a low-level delay that does not rely on interrupts to function
         // Do not spin forever, to avoid thermal risks if heaters are enabled and
         // watchdog does not work.
-        DELAY_US(10000000);
+        for (int i = 10000; i--;) DELAY_US(1000UL);
         ENABLE_ISRS();
         SERIAL_ECHOLNPGM("FAILURE: Watchdog did not trigger board reset.");
       }