move hexdump() from logging.c to utils.c
diff --git a/src/rsl.c b/src/rsl.c
index 10fba9b..3bfeffb 100644
--- a/src/rsl.c
+++ b/src/rsl.c
@@ -22,6 +22,7 @@
  */
 
 #include <stdint.h>
+#include <stdio.h>
 #include <errno.h>
 
 #include <osmocore/tlv.h>