Update the DeviceType property from string to enum

As defined in the PDIs [1], the DeviceType property of PCIeDevice
interface has been updated from "string" to "enum". This commit updates
the corresponding values.

[1] https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/81625

Change-Id: I4f5f5f17f7faee10c9b804b44e941ed551953d8c
Signed-off-by: Thang Tran <thuutran@amperecomputing.com>
diff --git a/src/peci_pcie.cpp b/src/peci_pcie.cpp
index ad1bbfd..26cd3a9 100644
--- a/src/peci_pcie.cpp
+++ b/src/peci_pcie.cpp
@@ -559,11 +559,15 @@
     }
     if (multiFunc)
     {
-        setPCIeProperty(clientAddr, bus, dev, deviceTypeName, "MultiFunction");
+        setPCIeProperty(
+            clientAddr, bus, dev, deviceTypeName,
+            "xyz.openbmc_project.Inventory.Item.PCIeDevice.DeviceTypes.MultiFunction");
     }
     else
     {
-        setPCIeProperty(clientAddr, bus, dev, deviceTypeName, "SingleFunction");
+        setPCIeProperty(
+            clientAddr, bus, dev, deviceTypeName,
+            "xyz.openbmc_project.Inventory.Item.PCIeDevice.DeviceTypes.SingleFunction");
     }
 
     // Set PCIe Generation