The blowfish-x86_64 encryption functions have an unused argument. Remove
it.

This involves:
 1 - Removing xor_block() macros.
 2 - Removing handling of fourth argument from __blowfish_enc_blk{,_4way}()
     functions.
 3 - Renaming __blowfish_enc_blk{,_4way}() to blowfish_enc_blk{,_4way}().
 4 - Removing the blowfish_enc_blk{,_4way}() wrappers from
     blowfish_glue.c
 5 - Temporarily using SYM_TYPED_FUNC_START for now indirectly-callable
     encode functions.
Signed-off-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>