Correct missing parameter from last upmerge

Signed-off-by: Joseivaldo Benito Junior <jrbenito@benito.qsl.br>

Marlin/example_configurations/delta/Configuration.h

 // and processor overload (too many expensive sqrt calls).
 #define DELTA_SEGMENTS_PER_SECOND 200
 
+// NOTE NB all values for DELTA_* values MOUST be floating point, so always have a decimal point in them
+
 // Center-to-center distance of the holes in the diagonal push rods.
 #define DELTA_DIAGONAL_ROD 250.0 // mm
 
 // Effective horizontal distance bridged by diagonal push rods.
 #define DELTA_RADIUS (DELTA_SMOOTH_ROD_OFFSET-DELTA_EFFECTOR_OFFSET-DELTA_CARRIAGE_OFFSET)
 
+#define DELTA_DIAGONAL_ROD_2 sq(DELTA_DIAGONAL_ROD)
+
 // Effective X/Y positions of the three vertical towers.
 #define SIN_60 0.8660254037844386
 #define COS_60 0.5