Add PFN related structures and definitions

sdk/xtdk/i686/xtstruct.h

@@ -42,6 +42,7 @@ typedef struct _KSWITCH_FRAME KSWITCH_FRAME, *PKSWITCH_FRAME;
 typedef struct _KTHREAD_INIT_FRAME KTHREAD_INIT_FRAME, *PKTHREAD_INIT_FRAME;
 typedef struct _KTRAP_FRAME KTRAP_FRAME, *PKTRAP_FRAME;
 typedef struct _KTSS KTSS, *PKTSS;
+typedef struct _MMPFN MMPFN, *PMMPFN;
 typedef struct _MMPTE_HARDWARE MMPTE_HARDWARE, *PMMPTE_HARDWARE;
 typedef struct _MMPTE_LEGACY_HARDWARE MMPTE_LEGACY_HARDWARE, *PMMPTE_LEGACY_HARDWARE;
 typedef struct _MMPTE_LEGACY_LIST MMPTE_LEGACY_LIST, *PMMPTE_LEGACY_LIST;