mmc: exynos_dw_mmc: add support for MMC HS200 and HS400 modes

mmc: exynos_dw_mmc: add support for MMC HS200 and HS400 modes

MMC HS200 and HS400 modes are already supported by the Exynos DW-MMC
driver in mainline Linux. Using that as reference, add support in the
U-Boot driver.

The maximum frequency was capped to 50000000, increase it to 200000000,
which is the required frequency for HS200/HS400. Moreover, add
MMC_MODE_HS200 and MMC_MODE_HS400 to host capailities. These changes
allow both host and card to recognize support for HS200/HS400.

This change also includes a new ops function, namely execute_tuning.
Implementing it would mean that we can no longer rely on the default ops
provided by dw_mmc.c, thus a new ops instance is created with proper
fields. The execute_tuning function is modeled after the one available
in the Linux driver.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>