x86: ifdtool: Correct a debug() missing parameter

This is missing a parameter. Fix it to avoid a warning when debug is
enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

tools/ifdtool.c

@@ -54,7 +54,8 @@ static struct fdbar_t *find_fd(char *image, int size)
 		return NULL;
 	}
 
-	debug("Found Flash Descriptor signature at 0x%08x\n", i);
+	debug("Found Flash Descriptor signature at 0x%08lx\n",
+	      (char *)ptr - image);
 
 	return (struct fdbar_t *)ptr;
 }