Optimize coordinate transformation

Pre-compute the combined position shift and home offset to save a
single float fetch-and-add per conversion. Great for delta/scara and
bed leveling.

Marlin/Marlin.h

 
 // Workspace offsets
 #if DISABLED(NO_WORKSPACE_OFFSETS)
-  extern float position_shift[XYZ];
-  extern float home_offset[XYZ];
-  #define LOGICAL_POSITION(POS, AXIS) ((POS) + home_offset[AXIS] + position_shift[AXIS])
-  #define RAW_POSITION(POS, AXIS)     ((POS) - home_offset[AXIS] - position_shift[AXIS])
+  extern float position_shift[XYZ],
+               home_offset[XYZ],
+               workspace_offset[XYZ];
+  #define LOGICAL_POSITION(POS, AXIS) ((POS) + workspace_offset[AXIS])
+  #define RAW_POSITION(POS, AXIS)     ((POS) - workspace_offset[AXIS])
 #else
   #define LOGICAL_POSITION(POS, AXIS) (POS)
   #define RAW_POSITION(POS, AXIS)     (POS)

Marlin/Marlin_main.cpp

   // Set by M206, M428, or menu item. Saved to EEPROM.
   float home_offset[XYZ] = { 0 };
 
+  // The above two are combined to save on computes
+  float workspace_offset[XYZ] = { 0 };
+
 #endif
 
 // Software Endstops are based on the configured limits.
    * at the same positions relative to the machine.
    */
   void update_software_endstops(const AxisEnum axis) {
-    const float offs = LOGICAL_POSITION(0, axis);
+    const float offs = workspace_offset[axis] = LOGICAL_POSITION(0, axis);
 
     #if ENABLED(DUAL_X_CARRIAGE)
       if (axis == X_AXIS) {
    * Since this changes the current_position, code should
    * call sync_plan_position soon after this.
    */
-  static void set_home_offset(AxisEnum axis, float v) {
+  static void set_home_offset(const AxisEnum axis, const float v) {
     current_position[axis] += v - home_offset[axis];
     home_offset[axis] = v;
     update_software_endstops(axis);