delta endstop adjustment configurable

Marlin/Conditionals_post.h

   // Stepper pulse duration, in cycles
   #define STEP_PULSE_CYCLES ((MINIMUM_STEPPER_PULSE) * CYCLES_PER_MICROSECOND)
 
+  #ifndef DELTA_ENDSTOP_ADJ_X
+    #define DELTA_ENDSTOP_ADJ_X 0
+  #endif
+  #ifndef DELTA_ENDSTOP_ADJ_Y
+    #define DELTA_ENDSTOP_ADJ_Y 0
+  #endif
+  #ifndef DELTA_ENDSTOP_ADJ_Z
+    #define DELTA_ENDSTOP_ADJ_Z 0
+  #endif
+
 #endif // CONDITIONALS_POST_H

Marlin/configuration_store.cpp

   #endif
 
   #if ENABLED(DELTA)
-    endstop_adj[X_AXIS] = endstop_adj[Y_AXIS] = endstop_adj[Z_AXIS] = 0;
+    endstop_adj[X_AXIS] = DELTA_ENDSTOP_ADJ_X;
+    endstop_adj[Y_AXIS] = DELTA_ENDSTOP_ADJ_Y;
+    endstop_adj[Z_AXIS] = DELTA_ENDSTOP_ADJ_Z;
     delta_radius =  DELTA_RADIUS;
     delta_diagonal_rod =  DELTA_DIAGONAL_ROD;
     delta_segments_per_second =  DELTA_SEGMENTS_PER_SECOND;