ASoC: S3C64XX: I2S: Move RATE and FMT defines to header

In order for the RATE and FMT defines to be reuseable in future by the
i2sv4 driver, move the MACROs out to the header file.

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>