dt-bindings: input: Add compatible string for SC2721 and SC2730

Add new compatible strings to support sc2730 and sc2721 which are
two varieties of SC27XX family.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201117034949.47877-4-zhang.lyra@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/sprd,sc27xx-vibrator.yaml

@@ -15,6 +15,8 @@ maintainers:
 properties:
   compatible:
     enum:
+      - sprd,sc2721-vibrator
+      - sprd,sc2730-vibrator
       - sprd,sc2731-vibrator
 
   reg: