rate_ctr: No need to include the inttypes.h

There should not be any u_int*_t types in this file, no need
to include this file. It is breaking compilation with the last
x86 build of GNU ARM for GCC 3.4.
diff --git a/src/rate_ctr.c b/src/rate_ctr.c
index f58b5c4..80ef55b 100644
--- a/src/rate_ctr.c
+++ b/src/rate_ctr.c
@@ -21,7 +21,6 @@
  */
 
 #include <stdint.h>
-#include <inttypes.h>
 #include <string.h>
 
 #include <osmocore/utils.h>