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/vegman_rx20_baseboard.json b/configurations/vegman_rx20_baseboard.json
index 3872798..8c6f0ba 100644
--- a/configurations/vegman_rx20_baseboard.json
+++ b/configurations/vegman_rx20_baseboard.json
@@ -523,6 +523,10 @@
                 "Type": "ADC"
             },
             {
+                "Name": "BMC",
+                "Type": "BMC"
+            },
+            {
                 "Address": "0x44",
                 "Bus": 3,
                 "Class": "i2c",