Extend the e_steps[] from int to long for allowing more than 32,767 E steps

Probably needed for long straight lines when using high microstepping

Marlin/stepper.cpp

@@ -95,7 +95,7 @@ volatile uint32_t Stepper::step_events_completed = 0; // The number of step even
   volatile unsigned char Stepper::eISR_Rate = 200; // Keep the ISR at a low rate until needed
 
   #if ENABLED(LIN_ADVANCE)
-    volatile int Stepper::e_steps[E_STEPPERS];
+    volatile long Stepper::e_steps[E_STEPPERS];
     int Stepper::extruder_advance_k = LIN_ADVANCE_K,
         Stepper::final_estep_rate,
         Stepper::current_estep_rate[E_STEPPERS],

Marlin/stepper.h

@@ -113,7 +113,7 @@ class Stepper {
       static unsigned char old_OCR0A;
       static volatile unsigned char eISR_Rate;
       #if ENABLED(LIN_ADVANCE)
-        static volatile int e_steps[E_STEPPERS];
+        static volatile long e_steps[E_STEPPERS];
         static int extruder_advance_k;
         static int final_estep_rate;
         static int current_estep_rate[E_STEPPERS]; // Actual extruder speed [steps/s]