dt-bindings: display: panel: Add bindings for Novatek nt36672a

Novatek nt36672a is a display driver IC that can drive DSI panel. It
is also present in the Tianma video mode panel, which is a FHD+ panel
with a resolution of 1080x2246 and 6.18 inches size. It is found in
some of the Poco F1 phones.

This patch adds the display driver for the IC, with support added for
this tianma fhd video mode panel.

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200902064407.30712-2-sumit.semwal@linaro.org