dt-bindings: panel-simple: Add compatible for Frida FRD350H54004 LCD

Add bindings documentation for the Frida 3.5" (320x240 pixels) 24-bit
TFT LCD panel.

v2: Switch documentation from plain text to YAML
v3: Simply add new compatible to panel-simple.yaml file instead of
    adding new file
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200113161741.32061-2-paul@crapouillou.net

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

@@ -37,6 +37,8 @@ properties:
       - auo,b116xa01
         # BOE NV140FHM-N49 14.0" FHD a-Si FT panel
       - boe,nv140fhmn49
+        # Frida FRD350H54004 3.5" QVGA TFT LCD panel
+      - frida,frd350h54004
         # GiantPlus GPM940B0 3.0" QVGA TFT LCD panel
       - giantplus,gpm940b0
         # Satoz SAT050AT40H12R2 5.0" WVGA TFT LCD panel