dt-bindings: msm: dsi-phy-28nm: Add missing qcom, dsi-phy-regulator-ldo-mode

Add in missing qcom,dsi-phy-regulator-ldo-mode to the 28nm DSI PHY.
When converting from .txt to .yaml we missed this one.

Fixes: 4dbe55c9 ("dt-bindings: msm: dsi: add yaml schemas for DSI bindings")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/516205/
Link: https://lore.kernel.org/r/20221229124438.504770-2-bryan.odonoghue@linaro.orgSigned-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

Documentation/devicetree/bindings/display/msm/dsi-phy-28nm.yaml

@@ -34,6 +34,10 @@ properties:
   vddio-supply:
     description: Phandle to vdd-io regulator device node.
 
+  qcom,dsi-phy-regulator-ldo-mode:
+    type: boolean
+    description: Indicates if the LDO mode PHY regulator is wanted.
+
 required:
   - compatible
   - reg