You can delete Form(s) 8396 from your return to remove the Mortgage Interest Certificate Credit. If the form reappears, you may have entered carryover amounts that you need to delete as well. To do that go back through the interview by answering yes on the first screen, so you can get back to the screen with the carryover amounts so you can delete them.
How to delete forms in TurboTax Online
How to delete forms in TurboTax Desktop