mmc: tegra: HW Command Queue Support for Tegra SDMMC

This patch adds HW Command Queue for supported Tegra SDMMC
controllers.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>