mmc: s3cmci: remove unneeded machine header include

The s3cmci driver does not use machine header mach/dma.h.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>