crypto: x86/ghash - use le128 instead of u128

The u128 struct type is going away, so make ghash-clmulni-intel use
le128 instead.  Note that the field names a and b swapped, as they were
backwards with u128.  (a is meant to be high-order and b low-order.)

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