arm64: tegra: Add missing timeout clock to Tegra210 SDMMC

commit 742af7e7 ("arm64: tegra: Add Tegra210 support")

Tegra210 uses separate SDMMC_LEGACY_TM clock for data timeout and
this clock is not enabled currently which is not recommended.

Tegra SDMMC advertises 12Mhz as timeout clock frequency in host
capability register.

So, this clock should be kept enabled by SDMMC driver.

Fixes: 742af7e7 ("arm64: tegra: Add Tegra210 support")
Cc: stable <stable@vger.kernel.org> # 5.4
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1598548861-32373-5-git-send-email-skomatineni@nvidia.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>