Convert to use the FPGA PWM cycle synchronization

This removes the need for the pwm feedback wire.

Change-Id: I8af9252cc81fd00d3904e785356deffb2ee89b00
diff --git a/y2019/wpilib_interface.cc b/y2019/wpilib_interface.cc
index eee7342..70cd6a2 100644
--- a/y2019/wpilib_interface.cc
+++ b/y2019/wpilib_interface.cc
@@ -460,7 +460,7 @@
     reader.set_stilts_absolute_pwm(make_unique<frc::DigitalInput>(3));
     reader.set_stilts_potentiometer(make_unique<frc::AnalogInput>(3));
 
-    reader.set_pwm_trigger(make_unique<frc::DigitalInput>(25));
+    reader.set_pwm_trigger(true);
     reader.set_vacuum_sensor(7);
 
     ::std::thread reader_thread(::std::ref(reader));