tests: tegra: Add VIC 4.2 support

The Video Image Composer (VIC) 4.2 can be found on NVIDIA Tegra194 SoCs.
It uses a different class (C5B6) that is slightly incompatible with the
class found on earlier generations, although it is backwards compatible
with the class implemented on Tegra186 (B1B6).

Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>