dt-bindings: display: qcom,sm8550-mdss: explicitly document mdp0-mem and cpu-cfg interconnect paths

The mdp1-mem is not supported on the SM8550 SoCs, and having maxItems=2
makes the bindings not clear if mdp0-mem/mdp1-mem or mdp0-mem/cpu-cfg is
required, so explicitly document the mdp0-mem/cpu-cfg interconnect and
add the cpu-cfg path in the example.

Suggested-by: Dmitry Baryshkov <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Neil Armstrong <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/637050/
Link: https://lore.kernel.org/r/202502[e-mail]
Signed-off-by: Dmitry Baryshkov <[e-mail]>

Documentation/devicetree/bindings/display/msm/qcom,sm8550-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 2
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 2
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":
···
         reg = <0x0ae00000 0x1000>;
         reg-names = "mdss";
 
-        interconnects = <&mmss_noc MASTER_MDP 0 &gem_noc SLAVE_LLCC 0>,
-                        <&mc_virt MASTER_LLCC 0 &mc_virt SLAVE_EBI1 0>;
-        interconnect-names = "mdp0-mem", "mdp1-mem";
+        interconnects = <&mmss_noc MASTER_MDP 0 &mc_virt SLAVE_EBI1 0>,
+                        <&gem_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_DISPLAY_CFG 0>;
+        interconnect-names = "mdp0-mem", "cpu-cfg";
 
         resets = <&dispcc DISP_CC_MDSS_CORE_BCR>;