vendor.sh: remove false error message

mkdst cycles through a bunch of outputted files
when running an extract function, to find the
right file as per defined checksums; if one is
found, it can still show errors for the others,
leading the user to think something is wrong.

remove their fear by removing this benign error.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/vendor.sh

@@ -183,7 +183,7 @@ fetch()
 
 mkdst()
 {
-	if bad_checksum "$1" "$2"; then
+	if bad_checksum "$1" "$2" 2>/dev/null; then
 		x_ rm -f "$2"
 	else
 		x_ mv "$2" "$_dl_bin"