ARM: S3C64XX: Modified according to SPI consolidation work

As SPI platform devices are consolidated to plat-samsung, some
corresponding changes are required in the s3c6410 varient SoCs.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>