Linux keyring support is protected by CONFIG_KEYUTILS.
We also need CONFIG_SECRET_KEYRING.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230414114252.1136-1-quintela@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>