drm: panel: add support for Synaptics TDDI series DSI panels

drm: panel: add support for Synaptics TDDI series DSI panels

Synaptics TDDI (Touch/Display Integration) panels utilize a single chip
for display and touch controllers. Implement a simple device driver for
such panels, along with its built-in LED backlight controller, and add
support for TD4101 and TD4300 panels in the driver.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251009-panel-synaptics-tddi-v5-2-59390997644e@disroot.org