include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/gsm/gsm48_ie.h b/include/osmocom/gsm/gsm48_ie.h
index f4fce25..8445486 100644
--- a/include/osmocom/gsm/gsm48_ie.h
+++ b/include/osmocom/gsm/gsm48_ie.h
@@ -1,5 +1,4 @@
-#ifndef _OSMOCORE_GSM48_IE_H
-#define _OSMOCORE_GSM48_IE_H
+#pragma once
 
 #include <stdint.h>
 #include <string.h>
@@ -113,5 +112,3 @@
 /* decode "Cell Channel Description" (10.5.2.1b) and other frequency lists */
 int gsm48_decode_freq_list(struct gsm_sysinfo_freq *f, uint8_t *cd,
 			   uint8_t len, uint8_t mask, uint8_t frqt);
-
-#endif