ARM: s3c64xx: MACH_SMDK6400 needs HSMMC1

This board uses both MMC controllers, so we need to enable
the Kconfig option to define the platform data.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: Tomasz Figa <tomasz.figa@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>