drm/bridge: ti-sn65dsi86: add link to datasheet

The bridge has pretty good docs, lets add a link to make them easier to
find.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190702154419.20812-2-robdclark@gmail.com