crypto: ccree - zap entire sg on aead request unmap

We were trying to be clever zapping out of the cache only the required
length out of scatter list on AEAD request completion and getting it
wrong.

As Knuth said: "when in douby, use brute force". Zap the whole length of
the scatter list.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>