crypto: arm/nhpoly1305 - eliminate unnecessary CFI wrapper

The arm architecture doesn't support CFI yet, and even if it did, the
new CFI implementation supports indirect calls to assembly functions.
Therefore, there's no need to use a wrapper function for nh_neon().

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>