linux-imx

drm/tegra: Add DSI support

This commit adds support for both DSI outputs found on Tegra. Only very
minimal functionality is implemented, so advanced features like ganged
mode won't work.

Due to the lack of other test hardware, some sections of the driver are
hardcoded to work with Dalmore.

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