Apply some general cleanup to code

Marlin/Marlin.h

 #include "fastio.h"
 #include "utility.h"
 
-
 #ifdef USBCON
   #include "HardwareSerial.h"
   #if ENABLED(BLUETOOTH)

Marlin/Marlin_main.cpp

       safe_delay(375);
     }
 
-    FORCE_INLINE void set_bltouch_deployed(const bool &deploy) {
+    void set_bltouch_deployed(const bool deploy) {
       bltouch_command(deploy ? BLTOUCH_DEPLOY : BLTOUCH_STOW);
       #if ENABLED(DEBUG_LEVELING_FEATURE)
         if (DEBUGGING(LEVELING)) {
 
         mbl.set_active(enable && mbl.has_mesh());
 
-        if (enable) planner.unapply_leveling(current_position);
+        if (enable && mbl.has_mesh()) planner.unapply_leveling(current_position);
       }
 
     #elif HAS_ABL && !ENABLED(AUTO_BED_LEVELING_UBL)
         gcode_G28();
         break;
 
-      #if PLANNER_LEVELING || HAS_ABL
+      #if PLANNER_LEVELING
         case 29: // G29 Detailed Z probe, probes the bed at 3 or more points,
                  // or provides access to the UBL System if enabled.
           gcode_G29();
     float normalized_dist, end[XYZE];
 
     // Split at the left/front border of the right/top square
-    int8_t gcx = max(cx1, cx2), gcy = max(cy1, cy2);
+    const int8_t gcx = max(cx1, cx2), gcy = max(cy1, cy2);
     if (cx2 != cx1 && TEST(x_splits, gcx)) {
       COPY(end, destination);
       destination[X_AXIS] = LOGICAL_X_POSITION(mbl.get_probe_x(gcx));
     float normalized_dist, end[XYZE];
 
     // Split at the left/front border of the right/top square
-    int8_t gcx = max(cx1, cx2), gcy = max(cy1, cy2);
+    const int8_t gcx = max(cx1, cx2), gcy = max(cy1, cy2);
     if (cx2 != cx1 && TEST(x_splits, gcx)) {
       COPY(end, destination);
       destination[X_AXIS] = LOGICAL_X_POSITION(bilinear_start[X_AXIS] + ABL_BG_SPACING(X_AXIS) * gcx);
 
 float calculate_volumetric_multiplier(float diameter) {
   if (!volumetric_enabled || diameter == 0) return 1.0;
-  return 1.0 / (M_PI * diameter * 0.5 * diameter * 0.5);
+  return 1.0 / (M_PI * sq(diameter * 0.5));
 }
 
 void calculate_volumetric_multipliers() {

Marlin/mesh_bed_leveling.h

     }
 
     int8_t probe_index_x(const float &x) const {
-      int8_t px = (x - (MESH_MIN_X) + (MESH_X_DIST) * 0.5) * (1.0 / (MESH_X_DIST));
+      int8_t px = (x - (MESH_MIN_X) + 0.5 * (MESH_X_DIST)) * (1.0 / (MESH_X_DIST));
       return (px >= 0 && px < (MESH_NUM_X_POINTS)) ? px : -1;
     }
 
     int8_t probe_index_y(const float &y) const {
-      int8_t py = (y - (MESH_MIN_Y) + (MESH_Y_DIST) * 0.5) * (1.0 / (MESH_Y_DIST));
+      int8_t py = (y - (MESH_MIN_Y) + 0.5 * (MESH_Y_DIST)) * (1.0 / (MESH_Y_DIST));
       return (py >= 0 && py < (MESH_NUM_Y_POINTS)) ? py : -1;
     }
 

Marlin/ultralcd.cpp

 
     static void _lcd_mesh_fine_tune(const char* msg) {
       static millis_t next_click = 0;
-      int16_t last_digit, movement;
+      int16_t last_digit;
       int32_t rounded;
 
       defer_return_to_status = true;