[dv/kmac] Remove unnecessary forever loops
[dv/kmac] Remove unnecessary forever loops

This PR removes two task with forever loop that was used for the cycle
accurate scb.

Signed-off-by: Cindy Chen <399ad771a111eac8923348b1e2af093034e5d4f1@opentitan.org>

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