ARM: S5P64X0: Upgrade platform device for I2S

Add more information to I2S platform_devices in order
to prepare them for new controller driver.
Also, discard duplicated gpio-cfg.

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