add typecast for Logging (#268)

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Description
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Typecast outgoing and incomingpublish count to unsigned longs to match
format specifier.
Test Steps
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core OTA demo had a build error due to format specifier used when
logging with coreMQTT. Adding these typecasts fixes the build error.
Checklist:
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- [X] I have tested my changes. No regression in existing tests.
- [ ] I have modified and/or added unit-tests to cover the code changes
in this Pull Request.

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source/core_mqtt.c

@@ -2612,7 +2612,7 @@ MQTTStatus_t MQTT_InitStatefulQoS( MQTTContext_t * pContext,
         LogError( ( "Arguments do not match: pOutgoingPublishRecords=%p, "
                     "outgoingPublishCount=%lu",
                     ( void * ) pOutgoingPublishRecords,
-                    outgoingPublishCount ) );
+                    ( unsigned long ) outgoingPublishCount ) );
         status = MQTTBadParameter;
     }
 
@@ -2624,7 +2624,7 @@ MQTTStatus_t MQTT_InitStatefulQoS( MQTTContext_t * pContext,
         LogError( ( "Arguments do not match: pIncomingPublishRecords=%p, "
                     "incomingPublishCount=%lu",
                     ( void * ) pIncomingPublishRecords,
-                    incomingPublishCount ) );
+                    ( unsigned long ) incomingPublishCount ) );
         status = MQTTBadParameter;
     }
     else if( pContext->appCallback == NULL )