Convert to use the FPGA PWM cycle synchronization

This removes the need for the pwm feedback wire.

Change-Id: I8af9252cc81fd00d3904e785356deffb2ee89b00
diff --git a/y2018/wpilib_interface.cc b/y2018/wpilib_interface.cc
index 2de1741..968de9e 100644
--- a/y2018/wpilib_interface.cc
+++ b/y2018/wpilib_interface.cc
@@ -683,7 +683,7 @@
     reader.set_claw_beambreak(make_unique<frc::DigitalInput>(8));
     reader.set_box_back_beambreak(make_unique<frc::DigitalInput>(9));
 
-    reader.set_pwm_trigger(make_unique<frc::DigitalInput>(25));
+    reader.set_pwm_trigger(true);
 
     reader.set_lidar_lite_input(make_unique<frc::DigitalInput>(22));