ARM: Odroid XU3: Fix the dwmci_exynos *priv data assignment for DM_MMC (sdr_timing)

ARM: Odroid XU3: Fix the dwmci_exynos *priv data assignment for DM_MMC (sdr_timing)

By convention for DM_MMC the host->priv is used to store struct udevice
*dev pointer.

Unfortunately, the legacy Exynos DW MMC code uses this field to
store pointer to dwmci_exynos_priv_data struct
Hence, we do need to get data in other way - namely by using container_of
when host pointer is present.
In this way the sdr_timing data is properly accessed.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>