crypto: twofish-x86_64-3way - module init/exit functions should be static

This caused conflict with camellia-x86_64 when compiled into kernel, same
function names and not static.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>