dt-bindings: display: waveshare,dsp2dpi: describe DSI2LVDS setup

dt-bindings: display: waveshare,dsp2dpi: describe DSI2LVDS setup

Several the Waveshare DSI LCD panel kits use DSI2LVDS ICN6202 bridge
together with the LVDS panels. Define new compatible for the on-kit
bridge setup (it is not itmized and it uses Waveshare prefix since the
rest of the integration details are not known).

Note: the ICN6202 / ICN6211 bridges are completely handled by the board
itself, they should not be programmed by the host (which otherwise might
override correct params), etc. As such, it doesn't make sense to use
those in the compat strings. I consider those to be an internal detail
of the setup.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260412-ws-lcd-v3-1-db22c2631828@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>