include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 8fa5d9a..9fcdddc 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -1,5 +1,4 @@
-#ifndef PROTO_GSM_04_08_H
-#define PROTO_GSM_04_08_H
+#pragma once
 
 #include <stdint.h>
 
@@ -1336,5 +1335,3 @@
 
 #define GSM_MACBLOCK_LEN	23
 #define GSM_MACBLOCK_PADDING	0x2b
-
-#endif /* PROTO_GSM_04_08_H */