This clears UHS_MODE_SELECT for timing modes <= MMC_HS_52.
When initializing to HS400 mode, the host controller downgrades to non-uhs
modes so clear UHS_MODE_SELECT at modes <= MMC_HS_52.
This fixes eMMC writes on j7200 EVM.
Fixes: 6067aa66b3 ("mmc: am654_sdhci: Add am654_sdhci_set_control_reg")
Signed-off-by: Judith Mendez <jm@ti.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>