dt-bindings: clock: google,gs101-clock: add HSI2 clock management unit

Add dt schema documentation and clock IDs for the High Speed Interface
2 (HSI2) clock management unit. This CMU feeds high speed interfaces
such as PCIe and UFS.

[AD: * keep CMUs in google,gs101.h sorted alphabetically
     * resolve minor merge conflicts in google,gs101-clock.yaml
     * s/ufs_embd/ufs    s/mmc_card/mmc

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://lore.kernel.org/r/20240429-hsi0-gs101-v3-1-f233be0a2455@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Documentation/devicetree/bindings/clock/google,gs101-clock.yaml

@@ -31,6 +31,7 @@ properties:
       - google,gs101-cmu-apm
       - google,gs101-cmu-misc
       - google,gs101-cmu-hsi0
+      - google,gs101-cmu-hsi2
       - google,gs101-cmu-peric0
       - google,gs101-cmu-peric1
 
@@ -97,6 +98,31 @@ allOf:
             - const: usb31drd
             - const: usbdpdbg
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - google,gs101-cmu-hsi2
+
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (24.576 MHz)
+            - description: High Speed Interface bus clock (from CMU_TOP)
+            - description: High Speed Interface pcie clock (from CMU_TOP)
+            - description: High Speed Interface ufs clock (from CMU_TOP)
+            - description: High Speed Interface mmc clock (from CMU_TOP)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: bus
+            - const: pcie
+            - const: ufs
+            - const: mmc
+
   - if:
       properties:
         compatible: