Add missing virtual ASoC DMA device and WM8580 as I2C slave,
so that the I2S can work on SMDK6450.

[kgene.kim@samsung.com: removed virtual ASoC DMA device
to avoid build error and it will be added next time]
Signed-off-by: NJassi Brar <jassi.brar@samsung.com>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
[kgene.kim@samsung.com: minor changed title]
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>