[cleanup] Fix clippy lints on opentitansession
[cleanup] Fix clippy lints on opentitansession

Signed-off-by: Chris Frantz <d3397dc265da044816f611610217f391e4e7ef39@google.com>

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