drm/tegra: hdmi: Rename tegra{2,3} to tegra{20,30}

Everything related to Tegra uses Tegra20 and Tegra30 instead of Tegra2
and Tegra3, respectively. Rename the TMDS arrays in the HDMI driver for
consistency.

Signed-off-by: Thierry Reding <treding@nvidia.com>