Revert "audio: fix pc speaker init"

Revert "audio: fix pc speaker init"

This reverts commit bd56d378842c238c8901536c06c20a4a51ee9761.

Turned out it isn't that simple as the device needs the pit object link.
So "-device isa-pcspk" isn't going wo work anyway.  We are in freeze, so
just reverting the thing is the best way to handle this for now, trying
to come up with something better can be done in the 4.1 devel cycle.

Also add a comment noting the object link.

Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20190328071121.21147-1-kraxel@redhat.com