[doc] Fix typo in TLUL docs
[doc] Fix typo in TLUL docs

Signed-off-by: Noah Moroze <efd87b0a520a6bffd7a1ad86a7f354ea1be2f761@mit.edu>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan