- Add support for L6470 Drivers.

- Both TMC, L6470 and pin-driven drivers work.
- All can be mixed and matched as needed.

Marlin/stepper.cpp

@@ -842,6 +842,11 @@ void st_init()
   #ifdef HAVE_TMCDRIVER
      tmc_init();
   #endif
+    // initialise L6470 Steppers
+  #ifdef HAVE_L6470DRIVER
+     L6470_init();
+  #endif
+  
   
   //Initialize Dir Pins
   #if defined(X_DIR_PIN) && X_DIR_PIN > -1