crypto: algif_aead - Require setkey before accept(2)

commit 2a2a251f110576b1d89efbd0662677d7e7db21a8 upstream.

Some cipher implementations will crash if you try to use them
without calling setkey first.  This patch adds a check so that
the accept(2) call will fail with -ENOKEY if setkey hasn't been
done on the socket yet.

Fixes: 400c40cf ("crypto: algif - add AEAD support")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>