[wpilibc] Remove incorrect timer rollover (#2523)

If the 64 bit FPGA timer rolls over, a 32 bit value is added for
the rollover, an artifact of when it was a 32 bit timer.
The 64 bit microsecond timer won't rollover for 500k years so remove the
check for simplicity.
Fixes #2504

wpilibc/src/main/native/include/frc2/Timer.h

@@ -144,9 +144,6 @@ class Timer {
    */
   static units::second_t GetMatchTime();
 
-  // The time, in seconds, at which the 32-bit FPGA timestamp rolls over to 0
-  static const units::second_t kRolloverTime;
-
  private:
   units::second_t m_startTime = 0_s;
   units::second_t m_accumulatedTime = 0_s;