Add missing KepRetireDpcList() routine forward reference

xtoskrnl/includes/ke.h

@@ -69,6 +69,10 @@ XTAPI
 VOID
 KeStartXtSystem(IN PKERNEL_INITIALIZATION_BLOCK Parameters);
 
+XTFASTCALL
+VOID
+KepRetireDpcList(IN PKPROCESSOR_CONTROL_BLOCK Prcb);
+
 XTAPI
 VOID
 KepSuspendNop(IN PKAPC Apc,