contrib/itmdump.c: fix implicit declaration warning

atoi used but stdlib.h wasn't included.
Also, include statements reordered alphabetically.

Change-Id: I7fcdbf3fa940a172204ec811399e1a7fdebdc979
Signed-off-by: Diego Herranz <diegoherranz@diegoherranz.com>
Reviewed-on: http://openocd.zylin.com/6312
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

contrib/itmdump.c

@@ -39,8 +39,9 @@
 
 #include <errno.h>
 #include <libgen.h>
-#include <stdio.h>
 #include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>