crypto: arm64/ghash - Fix incorrect output from ghash-neon

crypto: arm64/ghash - Fix incorrect output from ghash-neon

Commit 9a7c987fb92b ("crypto: arm64/ghash - Use API partial block
handling") made ghash_finup() pass the wrong buffer to
ghash_do_simd_update().  As a result, ghash-neon now produces incorrect
outputs when the message length isn't divisible by 16 bytes.  Fix this.

(I didn't notice this earlier because this code is reached only on CPUs
that support NEON but not PMULL.  I haven't yet found a way to get
qemu-system-aarch64 to emulate that configuration.)

Fixes: 9a7c987fb92b ("crypto: arm64/ghash - Use API partial block handling")
Cc: stable@vger.kernel.org
Reported-by: Diederik de Haas <diederik@cknow-tech.com>
Closes: https://lore.kernel.org/linux-crypto/DETXT7QI62KE.F3CGH2VWX1SC@cknow-tech.com/
Tested-by: Diederik de Haas <diederik@cknow-tech.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lore.kernel.org/r/20251209223417.112294-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>