ASoC: S3C64XX: Compress and generalize the CPU driver

The driver can be 'generalized' a bit by not hardcoding '2'(the number of
I2Sv3 controllers that the driver can handle) at many places, instead we
define a macro for it. That makes it easier to increase number of controllers
by changing the parameter at just one place, this will be useful when there is
support for newer SoCs, which have the same controller, only more in number.

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>