Enter both. You can enter two 1098 Mortgage Forms in TurboTax. See the screenshot below.
To enter mortgage interest, click on Where do I enter my 1098 mortgage interest statement?
Do not add the forms together.
As you go through the interview
section for 'Federal Taxes'; 'Deductions & Credits' you will be
prompted to enter information from Form 1098.
After you enter the first 1098 you will be returned to a summary screen.
Carefully read the summary screen, at the
lower left corner of the summary table is a Blue button "Add a lender".