dt-bindings: power: supply: pm8941-coincell: Don't require charging properties

It's fine for these properties to be absent, as the driver doesn't fail
without them and functions with settings inherited from the reset/previous
stage bootloader state.

Fixes: 6c463222 ("dt-bindings: power: supply: pm8941-coincell: Convert to DT schema format")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/qcom,pm8941-coincell.yaml

@@ -28,12 +28,18 @@ properties:
     maxItems: 1
 
   qcom,rset-ohms:
-    description: resistance (in ohms) for current-limiting resistor
+    description: |
+      Resistance (in ohms) for current-limiting resistor. If unspecified,
+      inherit the previous configuration (e.g. from bootloader or hardware
+      default value).
     enum: [ 800, 1200, 1700, 2100 ]
 
   qcom,vset-millivolts:
     $ref: /schemas/types.yaml#/definitions/uint32
-    description: voltage (in millivolts) to apply for charging
+    description: |
+      Voltage (in millivolts) to apply for charging. If unspecified, inherit
+      the previous configuration (e.g. from bootloader or hardware default
+      value).
     enum: [ 2500, 3000, 3100, 3200 ]
 
   qcom,charger-disable:
@@ -43,8 +49,6 @@ properties:
 required:
   - compatible
   - reg
-  - qcom,rset-ohms
-  - qcom,vset-millivolts
 
 additionalProperties: false