dt-bindings: Add support for samsung s6e3hf2 panel

The samsung s6e3hf2 panel is a 5.65" 1600x2560 AMOLED panel connected
using MIPI-DSI interfaces.

The s6e3hf2 is add to samsung,s6e3ha2.txt binding because it is a
panel similar to the s6e3ha2. So add the compatible string and
comments.

Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1492504836-19225-2-git-send-email-hoegeun.kwon@samsung.com