Add bindings for the TI NSPIRE simple display panels.

Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190806135437.7451-1-linus.walleij@linaro.orgSigned-off-by: Linus Walleij <linus.walleij@linaro.org>