dt-bindings: remoteproc: qcom,msm8916-mss-pil: Support platforms with one power domain

Add support for platforms such as MSM8974 which have the mx voltage rail
exposed as regulator and only cx voltage rail as power domain.

Signed-off-by: Matti Lehtimäki <matti.lehtimaki@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Link: https://lore.kernel.org/r/20250217-msm8226-modem-v5-1-2bc74b80e0ae@lucaweiss.eu
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Documentation/devicetree/bindings/remoteproc/qcom,msm8916-mss-pil.yaml

@@ -70,16 +70,17 @@ properties:
     items:
       - description: CX proxy power domain (control handed over after startup)
       - description: MX proxy power domain (control handed over after startup)
+                     (not valid for qcom,msm8974-mss-pil)
       - description: MSS proxy power domain (control handed over after startup)
                      (only valid for qcom,msm8953-mss-pil)
-    minItems: 2
+    minItems: 1
 
   power-domain-names:
     items:
       - const: cx
-      - const: mx
+      - const: mx # not valid for qcom,msm8974-mss-pil
       - const: mss # only valid for qcom,msm8953-mss-pil
-    minItems: 2
+    minItems: 1
 
   pll-supply:
     description: PLL proxy supply (control handed over after startup)
@@ -207,13 +208,38 @@ allOf:
       required:
         - power-domains
         - power-domain-names
-    else:
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,msm8909-mss-pil
+              - qcom,msm8916-mss-pil
+    then:
       properties:
         power-domains:
+          minItems: 2
           maxItems: 2
         power-domain-names:
+          minItems: 2
           maxItems: 2
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,msm8974-mss-pil
+    then:
+      properties:
+        power-domains:
+          maxItems: 1
+        power-domain-names:
+          maxItems: 1
+      required:
+        - mx-supply
+
   - if:
       properties:
         compatible: