vpnor: Rename mboxd_pnor_partition_table sources to backend

Change-Id: I6f0fff4ab54e011c1765fc04186e899754787641
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/vpnor/pnor_partition.cpp b/vpnor/pnor_partition.cpp
index 9854159..3625748 100644
--- a/vpnor/pnor_partition.cpp
+++ b/vpnor/pnor_partition.cpp
@@ -28,7 +28,7 @@
 #include <string>
 
 #include "common.h"
-#include "mboxd_pnor_partition_table.h"
+#include "vpnor/backend.h"
 
 namespace openpower
 {