Reduce fan blip time

Firmware/Configuration_adv.h

@@ -60,7 +60,7 @@
 // When first starting the main fan, run it at full speed for the
 // given number of milliseconds.  This gets the fan spinning reliably
 // before setting a PWM value. (Does not work with software PWM for fan on Sanguinololu)
-#define FAN_KICKSTART_TIME 800
+#define FAN_KICKSTART_TIME 400