Merge pull request #4038 from thinkyhead/rc_fix_heater_off

Fix broken DISABLE_HEATER macro

Marlin/temperature.cpp

   print_job_timer.stop();
 
   #define DISABLE_HEATER(NR) { \
-    setTargetHotend(NR, 0); \
+    setTargetHotend(0, NR); \
     soft_pwm[NR] = 0; \
     WRITE_HEATER_ ## NR (LOW); \
   }