ASoC: AC97: LN2440SBC: Switch to s3c-ac97.c

Switch to use s3c-ac97.c AC97 controller driver.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>