crypto: artpec6 - remove select on non-existing CRYPTO_SHA384

Since CRYPTO_SHA384 does not exists, Kconfig should not select it.
Anyway, all SHA384 stuff is in CRYPTO_SHA512 which is already selected.

Fixes: a21eb94fc4d3i ("crypto: axis - add ARTPEC-6/7 crypto accelerator driver")
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>