Added support for Gen3+ (Pins file only)

Added late z enable. (blddk request)
Only calculate look ahead if >2 moves in buffer.
Removed some FORCE_INLINE to save memory.

Signed-off-by: Erik van der Zalm <erik@vdzalm.eu>

Marlin/stepper.cpp

@@ -274,6 +274,9 @@ FORCE_INLINE void trapezoid_generator_reset() {
   acceleration_time = calc_timer(acc_step_rate);
   OCR1A = acceleration_time;
   OCR1A_nominal = calc_timer(current_block->nominal_rate);
+  #ifdef Z_LATE_ENABLE
+    if(current_block->steps_z > 0) enable_z();
+  #endif
   
 //    SERIAL_ECHO_START;
 //    SERIAL_ECHOPGM("advance :");