[otbn,dv] Model Bug Fix for Insns with Increment
[otbn,dv] Model Bug Fix for Insns with Increment

This commit includes a bug fix for implementing increments in the
model. The mask argument is removed and now is hard-coded in the
function body for 32 bits.

Fixes: #7805

Signed-off-by: Canberk Topal <e6b05429a51cc3258c31cb1f7836595b60921a29@lowrisc.org>

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