remove unneeded code

src/platforms/rp2040.h

@@ -24,9 +24,6 @@ void initTimer(uint32_t init_clock) {
 }
 
 void setTimer(uint32_t us_interval) {
-    if (Serial) {
-        Serial.flush();
-    }
     cancel_repeating_timer(&timer);
     // todo: actually should be -us_interval so that timer is set to start init_clock us after last tick, instead of init_clock us after finished processing last tick!
     add_repeating_timer_us(us_interval, &handlerISR, NULL, &timer);