dt-bindings: display: simple: Add Multi-Inno Technology MI0700S4T-6 panel

Add Multi-Inno Technology MI0700S4T-6 7" 800x480 DPI panel
compatible string.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: devicetree@vger.kernel.org
To: dri-devel@lists.freedesktop.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20211222133200.6586-1-marex@denx.de