ASoC: Disable S3C64xx support in Kconfig

Due to the process and communications issues with the 2.6.30 S3C
platform merges none of the underlying arch/arm code for S3C64xx audio
support made it into mainline, rendering the drivers useless.  Disable
them in Kconfig to avoid user confusion - users patching in the required
support can always reenable this too.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>