FROMGIT: crypto: arm/nhpoly1305 - add NEON-accelerated NHPoly1305

Add an ARM NEON implementation of NHPoly1305, an ε-almost-∆-universal
hash function used in the Adiantum encryption mode.  For now, only the
NH portion is actually NEON-accelerated; the Poly1305 part is less
performance-critical so is just implemented in C.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

(cherry picked from commit 16aae3595a9d41c97d983889b341c455779c2ecf
 https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git

 master)
Bug: 112008522
Test: As series, see Ic61c13b53facfd2173065be715a7ee5f3af8760b
Change-Id: Ibe2a3fd8ed8522f08e136e48b11492d9f01a3160
Signed-off-by: Eric Biggers <ebiggers@google.com>