Add "Exposes BMC" fields to configurations

The field is added to the JSON configurations such that when
Entity-Manager detects the corresponding board, an Inventory.Item.BMC
item is created to represent the BMC that runs the current OpenBMC
instance.

Signed-off-by: Sui Chen <suichen@google.com>
Change-Id: I9f1ba1ad107b183edd4a557a27a4865596d68d13
diff --git a/configurations/stp_baseboard.json b/configurations/stp_baseboard.json
index 44eb756..40c88a9 100644
--- a/configurations/stp_baseboard.json
+++ b/configurations/stp_baseboard.json
@@ -513,6 +513,10 @@
             "Type": "ADC"
         },
         {
+            "Name": "BMC",
+            "Type": "BMC"
+        },
+        {
             "Class": "Gpio",
             "GpioPolarity": "Low",
             "Name": "Chassis Intrusion Sensor",