mmc: s5p_sdhci: support the Driver model for Exynos

mmc: s5p_sdhci: support the Driver model for Exynos

This patch support the driver model for s5p_sdhci controller.
To support the legacy model, maintained the existing code.

Note: If use the Driver Model, it needs to modify the device-tree.
In future, will update the Device-tree and enable the configuratioin.
(CONFIG_BLK, CONFIG_DM_MMC and CONFING_DM_MMC_OPS)

Signed-off-by: Jaehoon Chung <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
Acked-by: Minkyu Kang <[email protected]>
Reviewed-by: Simon Glass <[email protected]>