ahci: explicitly reject bad engine states on post_load

ahci: explicitly reject bad engine states on post_load

Currently, we let ahci_cond_start_engines reject weird configurations
where either the DMA (CLB) or FIS engines are said to be started, but
their matching on/off control bit is toggled off.

There should be no way to achieve this, since any time you toggle the
control bit off, the status bit should always follow synchronously.

Preparing for a refactor in cond_start_engines, move the rejection logic
straight up into post_load.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1454103689-13042-4-git-send-email-jsnow@redhat.com