ASoC: ac97: Drop delayed device registration

We have all the information and dependencies we need to initialize and
register the device available in snd_soc_new_ac97_codec(). So there is no
need to delay the device registration until after the card itself as been
registered.

This makes the code significantly simpler and also makes it possible to use
the AC'97 device in the CODECs probe function. The later will be required to
be able to convert the AC'97 CODEC drivers to regmap.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>