arm64: tegra: Fix Tegra234 VDK node names

When the device-tree board file was added for the Tegra234 VDK simulator
it incorrectly used the names 'cbb' and 'sdhci' instead of 'bus' and
'mmc', respectively. The names 'bus' and 'mmc' are required by the
device-tree json-schema validation tools. Therefore, fix this by
renaming these nodes accordingly.

Fixes: 63944891 ("arm64: tegra: Initial Tegra234 VDK support")
Reported-by: Ashish Singhal <ashishsingha@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>