Revise PCI BW numbers on Rome

src/graph/topo.h

@@ -21,9 +21,9 @@
 #define SKL_CPUPCI_WIDTH 12
 #define P9_WIDTH 32
 #define NET_WIDTH 12           // 100Gbit
-#define ROME_QPI_WIDTH 24
-#define ROME_PCI_WIDTH 24
-#define ROME_CPUPCI_WIDTH 24
+#define ROME_QPI_WIDTH 18
+#define ROME_PCI_WIDTH 18
+#define ROME_CPUPCI_WIDTH 18
 
 // Intel CPU convert GPU P2P traffic into 64B PCI TLPs, to GPU
 // to GPU traffic consumed more PCI bandwidth.