Move C include to proper place

Change-Id: Id58d1820b94d54ce73ed40edb7747ef975890a7b
diff --git a/src/encoding.cpp b/src/encoding.cpp
index 1f96458..0241b39 100644
--- a/src/encoding.cpp
+++ b/src/encoding.cpp
@@ -28,9 +28,8 @@
 
 extern "C" {
 #include <osmocom/gprs/protocol/gsm_04_60.h>
-}
-
 #include <osmocom/gsm/protocol/gsm_04_08.h>
+}
 
 #include <stdbool.h>
 #include <errno.h>