[flash_ctrl] Modification of testplan according to comments in pull request
[flash_ctrl] Modification of testplan according to comments in pull request

Signed-off-by: Nikola Miladinovic <a10fbe9c8dedddf1bb7901cce09c2f247993e362@ensilica.com>

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