[aes] Hold EDN request until acknowledgment in case of fatal alerts
[aes] Hold EDN request until acknowledgment in case of fatal alerts

Previously, AES would drop a potentially asserted EDN request signal in
case of a fatal alert which could leave the EDN interface including CDC
in a weird state. With this commit, the request signal is always kept
asserted until acknowledgment which is similar to what other entropy
consumers do.

This is related to lowRISC/OpenTitan#10991.

Signed-off-by: Pirmin Vogel <386a7fc8e7338ed7899b4d9883c0ebec5de81366@lowrisc.org>

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