mkimage: Allow the original file size to be recorded

Allow the image handler to store the original input file size so that it
can reference it later.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

tools/imagetool.h

@@ -60,6 +60,7 @@ struct image_tool_params {
 	const char *comment;	/* Comment to add to signature node */
 	int require_keys;	/* 1 to mark signing keys as 'required' */
 	int file_size;		/* Total size of output file */
+	int orig_file_size;	/* Original size for file before padding */
 };
 
 /*