cbfstool: don't use endian to fix BSD hosts

endian.h lives in under sys on the BSDs. Replace htole32() with
swab32(htonl(..)) as a proxy for little endian operations.

Change-Id: I84a88f6882b6c8f14fb089e4b629e916386afe4d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11695
Tested-by: build bot (Jenkins)
Reviewed-by: Idwer Vollering <vidwer@gmail.com>
Reviewed-by: Jonathan A. Kollasch <jakllsch@kollasch.net>

util/cbfstool/cbfstool.c

@@ -19,7 +19,6 @@
  * Foundation, Inc.
  */
 
-#include <endian.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -272,7 +271,7 @@ static int cbfs_add_master_header(void)
 	// TODO: when we have a BE target, we'll need to store this as BE
 	*(uint32_t *)(buffer_get(&image.buffer) +
 		buffer_size(&image.buffer) - 4) =
-		htole32(header_offset);
+		swab32(htonl(header_offset));
 
 	ret = 0;