bloblist: Zero records when adding

It is convenient for bloblist to zero out the contents of a records when
it is added. This saves the callers having to do it.

Update the API accordingly.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/bloblist.c

@@ -73,6 +73,9 @@ static int bloblist_addrec(uint tag, int size, struct bloblist_rec **recp)
 	rec->hdr_size = sizeof(*rec);
 	rec->size = size;
 	rec->spare = 0;
+
+	/* Zero the record data */
+	memset(rec + 1, '\0', rec->size);
 	*recp = rec;
 
 	return 0;