You may have told TurboTax that you had a mortgage.

1. Type 1098 in search in the upper right
2. Select Jump to 1098
3. If you land on Your 1098 info so far, click on the trash can next to the mortgage lender and continue
4. If you land somewhere else, fill in dummy info and repeat the steps to jump and delete

If you previously had a mortgage, Turbotax will create a blank 1098 for you to fill in.  If you no longer have the mortgage, click "visit" or "revisit" the mortgage section, locate the name of the lender attached to the blank 1098, and delete the blank 1098 (I believe there is a trash can icon.)