dt-bindings: usb: samsung,exynos-dwc3: add exynos7870 support

Document compatible string for Exynos7870 DWC3-compatible USB 2.0
driver. The devicetree node requires three clocks, named "bus_early",
"ref", and "ctrl".

Unlike other variants, Exynos7870's USB controller requires a single
3.0V regulator. Assert that the other 1.0V regulator requirement is
enforced on variants individually other than Exynos7870's.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250301-exynos7870-usb-v3-1-f01697165d19@disroot.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/samsung,exynos-dwc3.yaml

@@ -17,6 +17,7 @@ properties:
           - samsung,exynos5250-dwusb3
           - samsung,exynos5433-dwusb3
           - samsung,exynos7-dwusb3
+          - samsung,exynos7870-dwusb3
           - samsung,exynos850-dwusb3
       - items:
           - const: samsung,exynos990-dwusb3
@@ -56,7 +57,6 @@ required:
   - clock-names
   - ranges
   - '#size-cells'
-  - vdd10-supply
   - vdd33-supply
 
 allOf:
@@ -76,6 +76,8 @@ allOf:
             - const: susp_clk
             - const: link_aclk
             - const: link_pclk
+      required:
+        - vdd10-supply
 
   - if:
       properties:
@@ -90,6 +92,8 @@ allOf:
         clock-names:
           items:
             - const: usbdrd30
+      required:
+        - vdd10-supply
 
   - if:
       properties:
@@ -107,6 +111,8 @@ allOf:
             - const: susp_clk
             - const: phyclk
             - const: pipe_pclk
+      required:
+        - vdd10-supply
 
   - if:
       properties:
@@ -123,6 +129,24 @@ allOf:
             - const: usbdrd30
             - const: usbdrd30_susp_clk
             - const: usbdrd30_axius_clk
+      required:
+        - vdd10-supply
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-dwusb3
+    then:
+      properties:
+        clocks:
+          minItems: 3
+          maxItems: 3
+        clock-names:
+          items:
+            - const: bus_early
+            - const: ref
+            - const: ctrl
 
   - if:
       properties:
@@ -138,6 +162,8 @@ allOf:
           items:
             - const: bus_early
             - const: ref
+      required:
+        - vdd10-supply
 
 additionalProperties: false