mtd: add Samsung SoC OneNAND driver

This patch adds a driver for OneNAND controller on Samsung SoCs.
Following SoCs are supported: S3C6400, S3C6410, S5PC100 and S5PC110.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>