dt-bindings: mmc: tegra: Add tmclk for Tegra210 and later

dt-bindings: mmc: tegra: Add tmclk for Tegra210 and later

commit b5a84ecf025a ("mmc: tegra: Add Tegra210 support")

Tegra210 and later uses separate SDMMC_LEGACY_TM clock for data
timeout.

So, this patch adds "tmclk" to Tegra sdhci clock property in the
device tree binding.

Fixes: b5a84ecf025a ("mmc: tegra: Add Tegra210 support")
Cc: stable <stable@vger.kernel.org> # 5.4
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1598548861-32373-4-git-send-email-skomatineni@nvidia.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>