dt-bindings: arm: rockchip: Add gru-scarlet sku{2,4} variants

The Gru-Scarlet family includes a variety of SKU identifiers, using
parts of a 3-bit space {0..7}. SKU2 and SKU4 devices (under a few
different manufacturer names) also use the Innolux display.

For reference, the original vendor tree source:

CHROMIUM: arm64: dts: rockchip: add sku{0,2,4} compatibility
https://chromium.googlesource.com/chromiumos/third_party/kernel/+/f6ed665c9e2eb37fb2680debbb36ec9fb0e8fb97

CHROMIUM: arm64: dts: rockchip: scarlet: add SKU0 device tree
https://chromium.googlesource.com/chromiumos/third_party/kernel/+/9987c8776f4b087d135d761e59f7fa6cc83fc7fcSigned-off-by: Brian Norris <briannorris@chromium.org>
Link: https://lore.kernel.org/r/20220817123350.1.Ibb15bab32dbfa0d89f86321c4eae7adbc8d7ad4a@changeidSigned-off-by: Heiko Stuebner <heiko@sntech.de>

Documentation/devicetree/bindings/arm/rockchip.yaml

@@ -373,30 +373,55 @@ properties:
           - const: google,gru
           - const: rockchip,rk3399
 
-      - description: Google Scarlet - Innolux display (Acer Chromebook Tab 10)
+      - description: |
+          Google Scarlet - Innolux display (Acer Chromebook Tab 10 and more)
         items:
+          - const: google,scarlet-rev15-sku2
+          - const: google,scarlet-rev15-sku4
           - const: google,scarlet-rev15-sku6
           - const: google,scarlet-rev15
+          - const: google,scarlet-rev14-sku2
+          - const: google,scarlet-rev14-sku4
           - const: google,scarlet-rev14-sku6
           - const: google,scarlet-rev14
+          - const: google,scarlet-rev13-sku2
+          - const: google,scarlet-rev13-sku4
           - const: google,scarlet-rev13-sku6
           - const: google,scarlet-rev13
+          - const: google,scarlet-rev12-sku2
+          - const: google,scarlet-rev12-sku4
           - const: google,scarlet-rev12-sku6
           - const: google,scarlet-rev12
+          - const: google,scarlet-rev11-sku2
+          - const: google,scarlet-rev11-sku4
           - const: google,scarlet-rev11-sku6
           - const: google,scarlet-rev11
+          - const: google,scarlet-rev10-sku2
+          - const: google,scarlet-rev10-sku4
           - const: google,scarlet-rev10-sku6
           - const: google,scarlet-rev10
+          - const: google,scarlet-rev9-sku2
+          - const: google,scarlet-rev9-sku4
           - const: google,scarlet-rev9-sku6
           - const: google,scarlet-rev9
+          - const: google,scarlet-rev8-sku2
+          - const: google,scarlet-rev8-sku4
           - const: google,scarlet-rev8-sku6
           - const: google,scarlet-rev8
+          - const: google,scarlet-rev7-sku2
+          - const: google,scarlet-rev7-sku4
           - const: google,scarlet-rev7-sku6
           - const: google,scarlet-rev7
+          - const: google,scarlet-rev6-sku2
+          - const: google,scarlet-rev6-sku4
           - const: google,scarlet-rev6-sku6
           - const: google,scarlet-rev6
+          - const: google,scarlet-rev5-sku2
+          - const: google,scarlet-rev5-sku4
           - const: google,scarlet-rev5-sku6
           - const: google,scarlet-rev5
+          - const: google,scarlet-rev4-sku2
+          - const: google,scarlet-rev4-sku4
           - const: google,scarlet-rev4-sku6
           - const: google,scarlet-rev4
           - const: google,scarlet