Fix stringop truncation warning from GCC 8.2 (#1393)

The next line adds a null terminator, but it's cleaner to just do a
std::memcpy() since the code already assumes a null terminator exists in
the source string.

hal/src/main/native/sim/DriverStation.cpp

@@ -149,8 +149,7 @@ char* HAL_GetJoystickName(int32_t joystickNum) {
   SimDriverStationData->GetJoystickDescriptor(joystickNum, &desc);
   size_t len = std::strlen(desc.name);
   char* name = static_cast<char*>(std::malloc(len + 1));
-  std::strncpy(name, desc.name, len);
-  name[len] = '\0';
+  std::memcpy(name, desc.name, len + 1);
   return name;
 }