This support article contains the instructions you need to reset the device in this situation:
"If you see the Restore screen on your iPhone, iPad, or iPod touch" click here --> https://support.apple.com/HT203122
- What to do if you get a restore error when you try to update or restore; click here --> http://support.apple.com/HT204770
- If you don't see a restore error, but still see the Connect to iTunes screen, or If you can't force a restart because one of your buttons is broken or stuck, contact Apple Support; click here --> https://getsupport.apple.com/?caller=kbase&SG=SG003&category_id=SC0091&symptom_id=20276
If your computer doesn't recognize your iPhone, iPad, or iPod, click here --> https://support.apple.com/HT204095