dt-bindings: clock: qcom: glymur-gcc: Add missing CX power domain

The GDSCs provided by the Glymur GCC are supplied by the RPMh CX power
domain. Model that parent domain in the GCC binding so the provider can
describe the dependency in devicetree.

Add a single CX power-domain entry to the binding and make it required,
matching the hardware description needed by the GCC node.

Fixes: ee2d967030 ("dt-bindings: clock: qcom: document the Glymur Global Clock Controller")
Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260715-glymur-fix-gcc-cx-scaling-v3-1-72eb5adad156@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Documentation/devicetree/bindings/clock/qcom,glymur-gcc.yaml

@@ -65,9 +65,15 @@ properties:
       - description: USB4 PHY 2 pcie pipe clock source
       - description: USB4 PHY 2 Max pipe clock source
 
+  power-domains:
+    description:
+      A phandle and PM domain specifier for the CX power domain.
+    maxItems: 1
+
 required:
   - compatible
   - clocks
+  - power-domains
   - '#power-domain-cells'
 
 allOf:
@@ -78,6 +84,7 @@ unevaluatedProperties: false
 examples:
   - |
     #include <dt-bindings/clock/qcom,rpmh.h>
+    #include <dt-bindings/power/qcom-rpmpd.h>
     clock-controller@100000 {
       compatible = "qcom,glymur-gcc";
       reg = <0x100000 0x1f9000>;
@@ -113,6 +120,7 @@ examples:
                <&usb4_phy_0_pcie_pipe>, <&usb4_phy_0_max_pipe>,
                <&usb4_phy_1_pcie_pipe>, <&usb4_phy_1_max_pipe>,
                <&usb4_phy_2_pcie_pipe>, <&usb4_phy_2_max_pipe>;
+      power-domains = <&rpmhpd RPMHPD_CX>;
       #clock-cells = <1>;
       #reset-cells = <1>;
       #power-domain-cells = <1>;