core/utils.h: move includes to the top

Having all inculdes listed in one place is a common good
practice, which prevents one from adding duplicates.

Change-Id: I3f52189d5e8f9afafc39525e95385a085f8f850a
diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 10063cb..976d4a8 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -1,6 +1,8 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
 
 #include <osmocom/core/backtrace.h>
 #include <osmocom/core/talloc.h>
@@ -30,9 +32,6 @@
 /*! Copy a C-string into a sized buffer using sizeof to detect buffer's size */
 #define OSMO_STRLCPY_ARRAY(array, src) osmo_strlcpy(array, src, sizeof(array))
 
-#include <stdint.h>
-#include <stdio.h>
-
 /*! A mapping between human-readable string and numeric value */
 struct value_string {
 	unsigned int value;	/*!< numeric value */