ASoC: Drop ac97_control initialization from CODEC driver DAIs

This is no longer necessary as there is no code anymore that uses this for
CODEC DAIs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>