crypto: x86/poly1305 - import unmodified cryptogams implementation

These x86_64 vectorized implementations come from Andy Polyakov's
CRYPTOGAMS implementation, and are included here in raw form without
modification, so that subsequent commits that fix these up for the
kernel can see how it has changed.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>