crypto: x86/glue-helper - drop XTS helper routines

The glue helper's XTS routines are no longer used, so drop them.

Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>