include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/core/logging.h b/include/osmocom/core/logging.h
index 1d57e22..caeea06 100644
--- a/include/osmocom/core/logging.h
+++ b/include/osmocom/core/logging.h
@@ -1,5 +1,4 @@
-#ifndef _OSMOCORE_LOGGING_H
-#define _OSMOCORE_LOGGING_H
+#pragma once
 
 /*! \defgroup logging Osmocom logging framework
  *  @{
@@ -216,5 +215,3 @@
 extern struct llist_head osmo_log_target_list;
 
 /*! @} */
-
-#endif /* _OSMOCORE_LOGGING_H */