include: Add MmGetSystemRoutineAddress definition.

include/ddk/wdm.h

@@ -1421,6 +1421,7 @@ PVOID     WINAPI MmAllocateContiguousMemory(SIZE_T,PHYSICAL_ADDRESS);
 PVOID     WINAPI MmAllocateNonCachedMemory(SIZE_T);
 PMDL      WINAPI MmAllocatePagesForMdl(PHYSICAL_ADDRESS,PHYSICAL_ADDRESS,PHYSICAL_ADDRESS,SIZE_T);
 void      WINAPI MmFreeNonCachedMemory(PVOID,SIZE_T);
+void *    WINAPI MmGetSystemRoutineAddress(UNICODE_STRING*);
 PVOID     WINAPI MmMapLockedPagesSpecifyCache(PMDL,KPROCESSOR_MODE,MEMORY_CACHING_TYPE,PVOID,ULONG,ULONG);
 MM_SYSTEMSIZE WINAPI MmQuerySystemSize(void);
 void      WINAPI MmProbeAndLockPages(PMDLX, KPROCESSOR_MODE, LOCK_OPERATION);