dt-bindings: power: reset: qcom-pon: Only allow reboot-mode pre-pmk8350

As pointed out by Shazad [1], PMICs using a separate HLOS+PBS scheme
(so PMK8350 and newer) are expected to pass reboot mode data through SDAM,
as the reboot mode registers are absent in the HLOS reg space.

Limit the reboot-mode.yaml inclusion to PMICs without a separate PBS
region.

[1] https://lore.kernel.org/linux-arm-msm/12f13183-c381-25f7-459e-62e0c2b19498@quicinc.com/

Fixes: 03fccdc7 ("dt-bindings: power: reset: qcom-pon: Add new compatible "qcom,pmk8350-pon"")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/reset/qcom,pon.yaml

@@ -56,7 +56,6 @@ required:
 unevaluatedProperties: false
 
 allOf:
-  - $ref: reboot-mode.yaml#
   - if:
       properties:
         compatible:
@@ -66,6 +65,9 @@ allOf:
               - qcom,pms405-pon
               - qcom,pm8998-pon
     then:
+      allOf:
+        - $ref: reboot-mode.yaml#
+
       properties:
         reg:
           maxItems: 1