arm64: tegra: Add missing timeout clock to Tegra186 SDMMC nodes

commit 39cb62cb ("arm64: tegra: Add Tegra186 support")

Tegra186 uses separate SDMMC_LEGACY_TM clock for data timeout and
this clock is not enabled currently which is not recommended.

Tegra186 SDMMC advertises 12Mhz as timeout clock frequency in host
capability register and uses it by default.

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

Fixes: 39cb62cb ("arm64: tegra: Add Tegra186 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/1598548861-32373-6-git-send-email-skomatineni@nvidia.com


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