dt-bindings: input: mediatek,pmic-keys: Drop incomplete example

The example for the Mediatek PMIC keys is incomplete as the binding is
the full PMIC, not just the sub-functions. It is preferred for MFD
examples to be complete in the top-level MFD device binding rather than
piecemeal in each sub-function binding.

This also fixes an undocumented (by schema) compatible warning for
"mediatek,mt6397".
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231128214816.3975893-1-robh@kernel.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/mediatek,pmic-keys.yaml

@@ -90,26 +90,4 @@ required:
 
 unevaluatedProperties: false
 
-examples:
-  - |
-    #include <dt-bindings/input/input.h>
-    #include <dt-bindings/interrupt-controller/arm-gic.h>
-
-    pmic {
-        compatible = "mediatek,mt6397";
-
-        keys {
-          compatible = "mediatek,mt6397-keys";
-          mediatek,long-press-mode = <1>;
-          power-off-time-sec = <0>;
-
-          key-power {
-            linux,keycodes = <KEY_POWER>;
-            wakeup-source;
-          };
-
-          key-home {
-            linux,keycodes = <KEY_VOLUMEDOWN>;
-          };
-        };
-    };
+...