Fix PartNumber and Serial Number from being ints

The code below this portion was converting it to an
int, avoid this by returning after conversion from
d-bus.

Tested: redfish/v1/Systems/system showed
    "PartNumber": "123456789",
    "PowerState": "On",
    "ProcessorSummary": {
        "Count": 0,
        "Status": {
            "State": "Disabled"
        }
    },
    "Processors": {
        "@odata.id": "/redfish/v1/Systems/system/Processors"
    },
    "SerialNumber": "123454321",

Change-Id: I1a48f5cef019e29f6276d52a36e55837ef4d211a
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/src/EntityManager.cpp b/src/EntityManager.cpp
index 5fe252c..5aa77bf 100644
--- a/src/EntityManager.cpp
+++ b/src/EntityManager.cpp
@@ -1290,6 +1290,7 @@
             {
                 std::visit([&](auto&& val) { keyPair.value() = val; },
                            foundDevicePair.second);
+                return;
             }
 
             // We probably just invalidated the pointer above, so set it to null