dt-bindings: display: panel: Add Raydium RM692E5

Raydium RM692E5 is a display driver IC used to drive AMOLED DSI panels.
Describe it.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230927-topic-fp5_disp-v2-1-7b5e1d1662a6@linaro.org