[keymgr] Fix reseed_ctrl edn requests
[keymgr] Fix reseed_ctrl edn requests

- Fixes #8260
- Ensure edn protocol is always followed no matter how software
  changes the reseed_interval

Signed-off-by: Timothy Chen <d7b2ae30d8c0f215facd721941273067fd1d14a2@google.com>

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