[REPOST PATCH v3 4/4] mmc: dw_mmc: Handle wp-gpios from device tree

On some SoCs (like exynos5250) you need to use an external GPIO for write protect. Add support for wp-gpios to the core dw_mmc driver since it could be useful across multiple SoCs. With this change I am able to make use of the write protect for the external SD slot on exynos5250-snow. Signed-off

[PATCH v3 4/4] mmc: dw_mmc: Handle wp-gpios from device tree

On some SoCs (like exynos5250) you need to use an external GPIO for write protect. Add support for wp-gpios to the core dw_mmc driver since it could be useful across multiple SoCs. With this change I am able to make use of the write protect for the external SD slot on exynos5250-snow. Signed-off