dt-bindings: ltk050h3146w: add compatible for LTK050H3148W-CTA6 variant

The LTK050H3148W-CTA6 is a 5.0" 720x1280 DSI display, whose driving
controller is a Himax HX8394-F, slightly different from LTK050H3146W by
its init sequence, mode details and mode flags.

Cc: Quentin Schulz <foss+kernel@0leil.net>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220131164723.714836-3-quentin.schulz@theobroma-systems.com

Documentation/devicetree/bindings/display/panel/leadtek,ltk050h3146w.yaml

@@ -17,6 +17,7 @@ properties:
     enum:
       - leadtek,ltk050h3146w
       - leadtek,ltk050h3146w-a2
+      - leadtek,ltk050h3148w
   reg: true
   backlight: true
   reset-gpios: true