Also avoid E direction inversions while coasting

Firmware/stepper.cpp

@@ -785,7 +785,7 @@ FORCE_INLINE void isr() {
 
 
 #ifdef LIN_ADVANCE
-    WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
+    if (e_steps) WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
     uint8_t la_state = 0;
 #endif
 
@@ -898,7 +898,7 @@ FORCE_INLINE void advance_isr() {
     if (step_events_completed.wide > LA_decelerate_after && current_adv_steps > final_adv_steps) {
         // decompression
         e_steps -= e_step_loops;
-        WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
+        if (e_steps) WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
         if(current_adv_steps > e_step_loops)
             current_adv_steps -= e_step_loops;
         else
@@ -908,7 +908,7 @@ FORCE_INLINE void advance_isr() {
     else if (step_events_completed.wide < LA_decelerate_after && current_adv_steps < max_adv_steps) {
         // compression
         e_steps += e_step_loops;
-        WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
+        if (e_steps) WRITE_NC(E0_DIR_PIN, e_steps < 0? INVERT_E0_DIR: !INVERT_E0_DIR);
         current_adv_steps += e_step_loops;
         nextAdvanceISR = eISR_Rate;
     }