dt-bindings: display: look for dsi* nodes in dsi-controller

Rob wrote:

    Uhhh, it's looking for dsi-controller(@.*)? which is not the common
    case found in dts files. We should fix that to dsi(@.*)?.

See: https://lore.kernel.org/dri-devel/20200319032222.GK29911@bogus/

Fix it.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408195109.32692-3-sam@ravnborg.org

Documentation/devicetree/bindings/display/dsi-controller.yaml

@@ -28,7 +28,7 @@ description: |
 
 properties:
   $nodename:
-    pattern: "^dsi-controller(@.*)?$"
+    pattern: "^dsi(@.*)?$"
 
   "#address-cells":
     const: 1
@@ -76,7 +76,7 @@ patternProperties:
 examples:
   - |
     #include <dt-bindings/gpio/gpio.h>
-    dsi-controller@a0351000 {
+    dsi@a0351000 {
         reg = <0xa0351000 0x1000>;
         #address-cells = <1>;
         #size-cells = <0>;