Remove unneded ac97 indirection accessing its state

Searching for "inspiration" to convert another device to qdev, I got
ac97.  Once I understood a bit of qdev, found that ac97 used a not needed
indirection.  To protect the unaware, just fixed it.

Later, Juan.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: malc <av1474@comtv.ru>
