[wpilibc] MotorSafety::GetDescription(): Return std::string (#3390)

This is only called in an error condition, so it's not necessary to over
optimize it.

wpilibc/src/main/native/include/frc/drive/RobotDriveBase.h

@@ -5,9 +5,9 @@
 #pragma once
 
 #include <memory>
+#include <string>
 
 #include <wpi/ArrayRef.h>
-#include <wpi/raw_ostream.h>
 
 #include "frc/MotorSafety.h"
 
@@ -66,7 +66,7 @@ class RobotDriveBase : public MotorSafety {
   void FeedWatchdog();
 
   void StopMotor() override = 0;
-  void GetDescription(wpi::raw_ostream& desc) const override = 0;
+  std::string GetDescription() const override = 0;
 
  protected:
   /**