Repair display throttling (#14960)

Marlin/src/module/planner.cpp

@@ -2037,6 +2037,7 @@ bool Planner::_populate_block(block_t * const block, bool split_move,
     if (was_enabled) DISABLE_STEPPER_DRIVER_INTERRUPT();
 
     block_buffer_runtime_us += segment_time_us;
+    block->segment_time_us = segment_time_us;
 
     if (was_enabled) ENABLE_STEPPER_DRIVER_INTERRUPT();
   #endif

Marlin/src/module/planner.h

@@ -155,7 +155,9 @@ typedef struct block_t {
     uint8_t valve_pressure, e_to_p_pressure;
   #endif
 
-  uint32_t segment_time_us;
+  #if HAS_SPI_LCD
+    uint32_t segment_time_us;
+  #endif
 
 } block_t;