fix unknown.h back as it was

correct fix is to fix ksfilter

svn path=/trunk/; revision=32276

reactos/include/ddk/unknown.h

@@ -1,5 +1,5 @@
-#ifndef __unknwn_h__
-#define __unknwn_h__
+#ifndef _UNKNOWN_H_
+#define _UNKNOWN_H_
 
 #ifdef __cplusplus
 extern "C" {
@@ -51,6 +51,5 @@ HRESULT
   IN  PUNKNOWN    OuterUnknown,
   IN  POOL_TYPE   PoolType
 );
-
 #endif