[DMILIB][UDMIHELP] Favor pragma once (#5472)

sdk/lib/dmilib/dmilib.h

@@ -1,13 +1,11 @@
 /*
  * PROJECT:     ReactOS DMI/SMBIOS Library
  * LICENSE:     GPL - See COPYING in the top level directory
- * FILE:        dmilib.h
  * PURPOSE:     SMBIOS table parsing functions
  * PROGRAMMERS: Timo Kreuzer ([email protected])
  */
 
-#ifndef DMILIB_H
-#define DMILIB_H
+#pragma once
 
 enum _ID_STRINGS
 {
@@ -35,5 +33,3 @@ ParseSMBiosTables(
     _In_reads_bytes_(TableSize) PVOID SMBiosTables,
     _In_ ULONG TableSize,
     _Inout_updates_(ID_STRINGS_MAX) PCHAR * Strings);
-
-#endif /* DMILIB_H */

sdk/lib/udmihelp/udmihelp.h

@@ -5,8 +5,7 @@
  * COPYRIGHT:   Copyright 2018 Stanislav Motylkov
  */
 
-#ifndef UDMIHELP_H
-#define UDMIHELP_H
+#pragma once
 
 #ifdef __cplusplus
 extern "C" {
@@ -36,5 +35,3 @@ FreeSMBiosData(
 #ifdef __cplusplus
 } // extern "C"
 #endif
-
-#endif /* UDMIHELP_H */