twofish-x86_64-3way uses functions from LRW and XTS modules, so selecting would
appear to be better option than using #ifdefs in twofish_glue_3way.c to
enable/disable LRW and XTS features.

This also fixes build problem when twofish-x86_64-3way would be build into
kernel but XTS/LRW are build as modules.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>