AP_Motors: fix for HAL_SITL rename

libraries/AP_Motors/AP_Motors_Class.h

@@ -72,7 +72,7 @@
 #define AP_MOTOR_ANY_LIMIT          0xFF
 
 // To-Do: replace this hard coded counter with a timer
-#if HAL_CPU_CLASS < HAL_CPU_CLASS_75 || CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL || CONFIG_HAL_BOARD == HAL_BOARD_LINUX
+#if HAL_CPU_CLASS < HAL_CPU_CLASS_75 || CONFIG_HAL_BOARD == HAL_BOARD_SITL || CONFIG_HAL_BOARD == HAL_BOARD_LINUX
  // slow start increments - throttle increase per (100hz) iteration.  i.e. 5 = full speed in 2 seconds
  #define AP_MOTOR_SLOW_START_INCREMENT           10      // max throttle ramp speed (i.e. motors can reach full throttle in 1 second)
  #define AP_MOTOR_SLOW_START_LOW_END_INCREMENT   2       // min throttle ramp speed (i.e. motors will speed up from zero to _spin_when_armed speed in about 1 second)