mmc: dw_mmc: use the cookie's enum values for post/pre_req()

This patch removed the meaningless value. Instead, use the cookie's enum
values for executing correctly.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

include/linux/mmc/dw_mmc.h

@@ -39,6 +39,12 @@ enum {
 	EVENT_DATA_ERROR,
 };
 
+enum dw_mci_cookie {
+	COOKIE_UNMAPPED,
+	COOKIE_PRE_MAPPED,	/* mapped by pre_req() of dwmmc */
+	COOKIE_MAPPED,		/* mapped by prepare_data() of dwmmc */
+};
+
 struct mmc_data;
 
 enum {