Control.Power.CapLimits: Add power cap limits interface

This interface will provide the minimum and maximum power cap values
supported. This will be hosted/written by OCC.Control and is replacing
the same properties from Control.Power.Cap.

The properties in Control.Power.Cap are hosted by Settings and the cap
limits had to temporarily be made writable so that OCC.Control could
write them.

Change-Id: Id24be182f7af8bfdc66d312a72b56afe172f8543
Signed-off-by: Chris Cain <cjcain@us.ibm.com>
diff --git a/yaml/xyz/openbmc_project/Control/Power/CapLimits.interface.yaml b/yaml/xyz/openbmc_project/Control/Power/CapLimits.interface.yaml
new file mode 100644
index 0000000..2fe322f
--- /dev/null
+++ b/yaml/xyz/openbmc_project/Control/Power/CapLimits.interface.yaml
@@ -0,0 +1,30 @@
+description: >
+    Implement to specify the power cap limits
+
+properties:
+    - name: MinPowerCapValue
+      type: uint32
+      flags:
+          - readonly
+      default: 0
+      description: The Minimum supported PowerCap setting.
+
+    - name: MaxPowerCapValue
+      type: uint32
+      flags:
+          - readonly
+      default: maxint
+      description: The Maximum supported PowerCap setting.
+
+    - name: MinSoftPowerCapValue
+      type: uint32
+      flags:
+          - readonly
+      default: 0
+      description: >
+          Minimum supported soft user PowerCap setting.
+          The min soft user PowerCap value is normally less than or equal to
+          the MinPowerCapValue. When the PowerCap is set to any value between
+          MinSoftPowerCapValue and MinPowerCapValue an attempt will be made to
+          maintain the cap but it will not be guaranted.
+