Powercap: add p8 support

P8 uses i2c-occ and powercap is not created.
Add P8 support by creating powercap object with i2c device name.

Fixes openbmc/openbmc#2688

Change-Id: Ia63070d63f4392cc4b084ab628cdbdcf4206c883
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/powercap.hpp b/powercap.hpp
index ddf2a74..6a77c9d 100644
--- a/powercap.hpp
+++ b/powercap.hpp
@@ -35,8 +35,10 @@
      * @param[in] occStatus - The occ status object
      */
     PowerCap(sdbusplus::bus::bus &bus,
-             Status &occStatus) :
+             Status &occStatus,
+             const std::string& occMasterName = OCC_MASTER_NAME) :
         bus(bus),
+        occMasterName(occMasterName),
         occStatus(occStatus),
         pcapMatch(
                 bus,
@@ -100,6 +102,9 @@
     /** @brief Reference to sdbus **/
     sdbusplus::bus::bus& bus;
 
+    /** @brief The master occ name */
+    std::string occMasterName;
+
     /* @brief OCC Status object */
     Status &occStatus;