dt-bindings: display: Add DT bindings for BOE HV070WSA-100 panel

The patch adds bindings to BOE HV070-WSA WSVGA panel. Bindings are
compatible with simple panel bindings.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Maciej Purski <m.purski@samsung.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1529396370-18761-5-git-send-email-m.purski@samsung.com