UPSTREAM: wireguard: Kconfig: select CRYPTO_BLAKE2S_ARM

When available, select the new implementation of BLAKE2s for 32-bit ARM.
This is faster than the generic C implementation.

Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

(cherry picked from commit a64bfe7ad42e329a1c63575d52c7927ad0f9e202)
Bug: 152722841
Bug: 178411248
Change-Id: I27b0d049b689c8ef5d44e01151aa8c78af1bdd0e
Signed-off-by: Eric Biggers <ebiggers@google.com>