qcacmn: Update credit flow control enable/disable in HTC

There are two ways to enable/disable HTC credit flow control. One is
in HTC itself with a static variable. The other is from the modules
who want to establish HTC service (e.g. WMI or HTT) by sending the
request. Make sure credit flow control enable/disable can be safely
done by other modules so that HTC layer can be converged.

Change-Id: I169c1ac7b410a7c9e7203c174bf1f1ec8a07ca06
CRs-fixed: 982024

htc/htc_services.c

@@ -126,17 +126,11 @@ A_STATUS htc_connect_service(HTC_HANDLE HTCHandle,
 			    HTC_CONNECT_FLAGS_DISABLE_CREDIT_FLOW_CTRL) {
 				disableCreditFlowCtrl = true;
 			}
-#if defined(HIF_USB)
+
 			if (!htc_credit_flow) {
 				disableCreditFlowCtrl = true;
 			}
-#else
-			/* Only enable credit for WMI service */
-			if (!htc_credit_flow
-			    && pConnectReq->service_id != WMI_CONTROL_SVC) {
-				disableCreditFlowCtrl = true;
-			}
-#endif
+
 			/* check caller if it wants to transfer meta data */
 			if ((pConnectReq->pMetaData != NULL) &&
 			    (pConnectReq->MetaDataLength <=