firmware-utils: fix various compiler warnings

mostly implicit defines due to missing includes plus one const that
shouldn't be one.

Signed-off-by: Felix Kaechele <felix@kaechele.ca>

SVN-Revision: 47865

tools/firmware-utils/src/wrt400n.c

@@ -7,12 +7,14 @@
  *
  *	Author: Sandeep Mistry
  */
+#include <arpa/inet.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "cyg_crc.h"