dt-bindings: display: panel: document Synaptics TDDI panel

dt-bindings: display: panel: document Synaptics TDDI panel

Document the Synaptics TDDI (Touch/Display Integration) panel hardware.
Along with the MIPI-DSI panel, these devices also have an in-built LED
backlight device and a touchscreen, all packed together in a single chip.

Also, add compatibles for supported panels - TD4101 and TD4300. Both
have the '-panel' suffix so as to remove any ambiguity between the panel
and touchscreen chips.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251009-panel-synaptics-tddi-v5-1-59390997644e@disroot.org