qcacld-3.0: Reduce log level in csr_roam_close_session

Reduce log level from error to debug in csr_roam_close_session.

Change-Id: Ifc486feefe2cde4635617f327fa5256bac202160
CRs-Fixed: 2317871

core/sme/src/csr/csr_api_roam.c

@@ -17454,7 +17454,7 @@ QDF_STATUS csr_roam_close_session(tpAniSirGlobal mac_ctx,
 	struct csr_roam_session *session;
 
 	if (!CSR_IS_SESSION_VALID(mac_ctx, session_id)) {
-		sme_err("session %d not found", session_id);
+		sme_debug("session %d not found", session_id);
 		return QDF_STATUS_E_INVAL;
 	}