include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/gsm/protocol/gsm_03_41.h b/include/osmocom/gsm/protocol/gsm_03_41.h
index 54365cb..b6efb5e 100644
--- a/include/osmocom/gsm/protocol/gsm_03_41.h
+++ b/include/osmocom/gsm/protocol/gsm_03_41.h
@@ -1,5 +1,4 @@
-#ifndef PROTO_GSM_03_41_H
-#define PROTO_GSM_03_41_H
+#pragma once
 
 #include <stdint.h>
 
@@ -47,5 +46,3 @@
 #define GSM341_GS_PLMN_WIDE		1
 #define GSM341_GS_LA_WIDE		2
 #define GSM341_GS_CELL_WIDE		3
-
-#endif /* PROTO_GSM_03_41_H */