Fix Coverity CID:1453685 'unreachable code' in aes_xts code.
Fix Coverity CID:1453685 'unreachable code' in aes_xts code.

Reviewed-by: Richard Levitte <5fb523282dd7956571c80524edc2dccfa0bd8234@openssl.org>
Reviewed-by: Kurt Roeckx <bb87b47479d83cec3c76132206933257ded727b2@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/9902)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl