ARM: S3C: Add missing selection of S3C_DEV_NAND in machine Kconfigs.

A number of machines that need s3c_device_nand present do not select
this in their Kconfig entries. Add the necessary selection of the
configuration S3C_DEV_NAND so that we avoid the following error:

arch/arm/mach-s3c2410/built-in.o: In function `bast_map_io':
arch/arm/mach-s3c2410/mach-bast.c:634: undefined reference to `s3c_device_nand'
arch/arm/mach-s3c2412/built-in.o: In function `s3c2412_init_uarts':
arch/arm/mach-s3c2412/s3c2412.c:109: undefined reference to `s3c_device_nand'
arch/arm/mach-s3c2412/built-in.o: In function `jive_machine_init':
arch/arm/mach-s3c2412/mach-jive.c:673: undefined reference to `s3c_device_nand'

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/arch/arm/mach-s3c6400/Kconfig b/arch/arm/mach-s3c6400/Kconfig
index f5af212..770b720 100644
--- a/arch/arm/mach-s3c6400/Kconfig
+++ b/arch/arm/mach-s3c6400/Kconfig
@@ -26,6 +26,7 @@
        bool "SMDK6400"
 	select CPU_S3C6400
 	select S3C_DEV_HSMMC
+	select S3C_DEV_NAND
 	select S3C6400_SETUP_SDHCI
 	help
 	  Machine support for the Samsung SMDK6400