ARM: S5P64X0: Segregate audio devices

Segregate I2S devices for S5P6440 and S5P6450.

Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>