Connect in recovery mode and restore, you'll get the option to reset the passcode during this process:
If you cannot remember the passcode, you will need to restore your device using the computer with which you last synced it. This allows you to reset your passcode and resync the data from the device (or restore from a backup). If you restore on a different computer that was never synced with the device, you will be able to unlock the device for use and remove the passcode, but your data will not be present. Refer to Updating and restoring iPhone, iPad and iPod touch software.
Just wait the amount of time it is asking you. Thats about all you can do.
Depending on the amount of time shown on the display, this could be years to wait for this user, I would rather choose to restore in that case.
Message was edited by: Ingo2711