arm64: tegra: Disable CQE Support for SDMMC4 on Tegra186

Enabling CQE support on Tegra186 Jetson TX2 has introduced a regression
that is causing accesses to the file-system on the eMMC to fail. Errors
such as the following have been observed ...

 mmc2: running CQE recovery
 mmc2: mmc_select_hs400 failed, error -110
 print_req_error: I/O error, dev mmcblk2, sector 8 flags 80700
 mmc2: cqhci: CQE failed to exit halt state

For now disable CQE support for Tegra186 until this issue is resolved.

Fixes: dfd3cb6f

 arm64: tegra: Add CQE Support for SDMMC4
Signed-off-by: Jonathan Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>