mmc: exynos_dw_mmc: use the exynos specific data structure

Clksel value is exynos specific value.
It removed "clksel_val" into dwmci_host and created the
"dwmci_exynos_priv_data" structure for exynos specific data.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/include/dwmmc.h b/include/dwmmc.h
index 109f7c8..86a5491 100644
--- a/include/dwmmc.h
+++ b/include/dwmmc.h
@@ -141,9 +141,9 @@
 	int dev_index;
 	int dev_id;
 	int buswidth;
-	u32 clksel_val;
 	u32 fifoth_val;
 	struct mmc *mmc;
+	void *priv;
 
 	void (*clksel)(struct dwmci_host *host);
 	void (*board_init)(struct dwmci_host *host);