Remove some dead code

The intention of the removed code was to check if the previous operation
carried. However this does not work. The "mask" value always ends up being
a constant and is all ones - thus it has no effect. This check is no longer
required because of the previous commit.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3832)