image_types_tegra.bbclass: add bootloader update payload support
image_types_tegra.bbclass: add bootloader update payload support

for tegra186 platforms, with some latent support for tegra194.

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

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