[entropy_src/dv] Minor scoreboarding updates
[entropy_src/dv] Minor scoreboarding updates

Updates the scoreboard to to more accurately the behavior particularly
around the SW_REGUPD register and the ERR_CODE registers.

Signed-off-by: Martin Lueker-Boden <7e82c17fafb3b7b91b3c3396a2f21a060e5a6c3d@wdc.com>

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