Parse I2C bus and address out of JSON config file

The I2C bus and address need to be passed down to the PowerSupply
constructor, so get those out of the JSON configuration file now.

Change I2C address format in JSON to be a string, without the
hexadecimal format since it needs to be appended to a string, allowing
to skip conversion from string to number and then from number back to
string.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Change-Id: I2707799bb60d1f4a9783a0403bc3e4920461b7a1
diff --git a/phosphor-power-supply/configurations/witherspoon/psu_config.json b/phosphor-power-supply/configurations/witherspoon/psu_config.json
index 6724ab0..eaa57aa 100644
--- a/phosphor-power-supply/configurations/witherspoon/psu_config.json
+++ b/phosphor-power-supply/configurations/witherspoon/psu_config.json
@@ -8,12 +8,12 @@
         {
             "Inventory" : "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply0",
             "Bus" : 3,
-            "Address" : "0x68"
+            "Address" : "0068"
         },
         {
             "Inventory" : "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply1",
             "Bus" : 3,
-            "Address" : "0x69"
+            "Address" : "0069"
         }
     ]
 }