image_types_tegra.bbclass: update for R28.1
image_types_tegra.bbclass: update for R28.1

Tegra210 now uses cboot, and loads U-Boot from
the LNX partition, like tegra186.

Signed-off-by: Matt Madison <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@madison.systems>

madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra