arm64: tegra: Enable command queue for Tegra186 SDMMC4

The workaround for a hardware bug preventing this from working has been
merged now, so command queue support can be enabled again for Tegra186.

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>