include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/gsm/milenage/aes_i.h b/src/gsm/milenage/aes_i.h
index 6b40bc7..c831757 100644
--- a/src/gsm/milenage/aes_i.h
+++ b/src/gsm/milenage/aes_i.h
@@ -12,8 +12,7 @@
  * See README and COPYING for more details.
  */
 
-#ifndef AES_I_H
-#define AES_I_H
+#pragma once
 
 #include "aes.h"
 
@@ -118,5 +117,3 @@
 #define AES_PRIV_SIZE (4 * 44)
 
 void rijndaelKeySetupEnc(u32 rk[/*44*/], const u8 cipherKey[]);
-
-#endif /* AES_I_H */