dt-bindings: panel-simple: Add compatible for GiantPlus GPM940B0

Add a compatible string for the GiantPlus GPM740B0 3" QVGA TFT LCD
panel, and remove the old giantplus,gpm740b0.txt documentation which is
now obsolete.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200109003000.119516-1-paul@crapouillou.net

Documentation/devicetree/bindings/display/panel/giantplus,gpm940b0.txt

-GiantPlus 3.0" (320x240 pixels) 24-bit TFT LCD panel
-
-Required properties:
-- compatible: should be "giantplus,gpm940b0"
-- power-supply: as specified in the base binding
-
-Optional properties:
-- backlight: as specified in the base binding
-- enable-gpios: as specified in the base binding
-
-This binding is compatible with the simple-panel binding, which is specified
-in simple-panel.txt in this directory.

Documentation/devicetree/bindings/display/panel/panel-simple.yaml

@@ -35,6 +35,8 @@ properties:
       - ampire,am800480r3tmqwa1h
         # AUO B116XAK01 eDP TFT LCD panel
       - auo,b116xa01
+        # GiantPlus GPM940B0 3.0" QVGA TFT LCD panel
+      - giantplus,gpm940b0
 
   backlight: true
   enable-gpios: true